Officially the most Horrible mom of the month

I think overall, I am a pretty good mom. I avoid buying take-out for my kids, I cook nice food for them, make sure they are warm and comfortable, try to be there for them whenever I can....etc. I think I generally deserve a "good mom" title.
Things changed after yesterday. Yesterday (Thursday), Emma's school threw a party for all the kids that have birthdays in October. The teachers sent home notes to parents asking for the birthday kids to bring in something for the party. We were assigned to get 20 bags of small size snack chips for Emma to take to school. Wednesday night, I went home really late, and all of a sudden I remembered we need to get the chips for Emma. So I told Derek and Derek said, it's ok, Shoppers Drug Mart closes at midnight, it's only 9:30pm we still have time. Since Derek said he would go out to get it, it got off my mind. Sure enough, Thursday afternoon as I was driving back to work after my appointment, I was thinking about Emma and her birthday party at school then I suddenly remember we didn't go out at all on Wednesday night to get the chips!!!! I felt terrible. How could we forget? I called the school and asked the teacher if the party was over and if I should run and get something to make up for it. The teacher told me the party was already going on and there were plenty of food other parents got for the kids to share. (hmm... so other parents didn't forget).
Haunted by this horrible feeling of being a loser mom, I went home after work. Trying to tell myself to relax and convince myself that I am not that bad a mom. so I went in the shower, as I was thinking to myself "what a relaxing evening today. We will go over to my in-laws for dinner, Emma has martial art class and Derek will pick her up....OOPS, where is JACK!!! I forgot to pick him up!!!" I jumped out of the shower and called Derek. Derek was so worried about me 'cos he called me many times and no one answered (I was in the shower). The school called Derek and asked if anyone was picking up Jack. So Derek was on his way to pick up Jack.
How can I forget about Jack?
That night, Emma told me "mom you forgot to send me stuff to bring to school" (I was secretly hoping she doesn't know about it) and I said "how did you know? who told you?" and Emma said, "everyone told me". OUCH! I felt so bad, I said "I am so sorry Emma, it was my fault. I forgot to get the chips for you and send it to school".... being sweet as always, Emma said "it's not your fault mommy, don't worry about it. it's ok".

So yes, I have only two kids and I already forgot both of them. I think that makes me the worst mom of the month. Sigh.