Raquel,
I am sure there is room for improvement. We all have room for improvement, but do not get down and stay there. You are a single parent, and that's just the reality. There are some areas where your weaknesses will just be revealed, and there is no one there to pull the slack. I went through a 'brain fog' for years after my husband died, and so it could be just part of being alone and doing it on your own. I did things alone for over two years with three children, and I constantly failed to keep on top of it all. Some things just had to go completely! I left our farm for a while, because I couldn't educate them and run a farm...my oldest had just turned 7 and I needed help! I learned to seek God's help and rest in Him.
When you see that you are lacking in an area, look to the Lord to help you with it. I mean it, pray and fast to the Lord to give you help and insight into how to work in out for yourself. Be comforted, your daughter will not remember you failure, she will be like my children and say, "Mom, thanks for doing your best when you had to do it all alone." It's likely that she means it when she says you are a good mom, because you are...you care about her, but you aren't perfect. Everything you do is for her, and it is not going to hurt her to see you fail in certain areas. It will teach her to pray for you, forgive, and give grace. It will also teach her to pitch in and be helpful where she can.
Some practical advice would be to keep a central calendar in an obvious place. For me, it was in the kitchen. (I am not a schedule person, btw.) It helped me to keep it simple, because I get overwhelmed if there are too many details sometimes. Anyway, you can teach her to help you by 'drawing' things instead of writing words...or both so that you know what you drew! Make a point to stop at the calendar just as soon as you come in from picking her up. I would get one with a pin board on the side, btw, because then you can just pin up invitations and appointment cards so that they are visible reminders that something's going on. Anyway, make a point to visit the calendar as soon as you walk in the door. Then you can write down new things right away while their fresh in your mind, and get the next days items ready to go for morning. Tell her to remind you about the 'schedule time with mommy' every day after school, and she will. I would also take this time to ask her about how her day went, look at her school papers (pin them up on the board maybe) and if there was anything special coming up that she was looking forward to or if there are any problems she's having. One last thing, when the teacher is talking to you about up coming events, write them down or ask her to, or if she is handing you papers, find a place to put them where they are very annoying...like, let them hang out of the top of your purse.
For repeat items, like the blanket, keep them in a central bag by your purse, or a 'school box' by the door, so that you're not looking everywhere for them. Again, let her help. Let her know that if things need to go to school, then she can help by putting them in the 'school' bag/box. When we are going somewhere special the next day, we try to lay all the clothes out the night before. (You may already do this) Anyway, it helps battle the morning rush, and promotes order.
Another thing I do personally, is write a list of things before bed each night about the following day. I still do this. I have a category for each person in our family. I sometimes don't even look at the list later, but it helps remind me of things (poor memory) and it helps me rest without things on my mind at night. I just write it down, and then it's out of my mind. I also do this for the month at times, and then pin it to my board...sort of a things I'd like to remember/accomplish list.
The last thing I will add, is do not let your 'schedule' run you. It is in place for your benefit, but when things are not normal the schedule can be scaled down or ignored. There are times when you just won't be on top of it all, despite your efforts, and it's alright. This still will not make you a bad mom. I can't stress enough that you need to just turn to God for help to get things ordered. It's not my nature to be organized, but God has helped me improve in this area for the sake of bringing glory to Him in my ministry as wife and mother. He desires to be our help, and He desires for us to do a good job where He has us. Ask God to lead you in making a reasonable plan for your household. I am very minimal in this area, but there are others who have a gift that may be able to advise you even better.
Oh, I had another thought, this really is the last thing! (I know this is getting long) DO NOT COMPARE YOURSELF TO OTHER MOTHERS!!!!! This is the best way to get discouraged and become hopeless about the situation. You don't know the situation of others, nor do you know their gifts. It's not important. God made you, and He can help you, and the only one you should compare yourself with is Christ. Not so that you can try to appear to be better, but so that you can imitate Him and conform to His image in a genuine guilt-free way. Take your eyes off of others, and look to Him to help you do your best and try to make improvements where you need them. You are Raquel, and your daughter was entrusted to you by God, He knows what you both need and how He wants to grow you.
The Lord bless you.