Why do I sweat the small stuff?

This morning. I got up earlier than usual. No. Not to run. To shower. I got home late from rehearsal and since Bea was still up I didn't want her to wait for me any longer to take a shower before she actually went to bed. So I quickly washed my face and crawled into bed with her. I intended to get up once she fell asleep and shower but I fell asleep and when I woke up it was 3:30 a.m.
Anyways. I took my shower a bit later and then went out to the kitchen to make Bea her lunch - since I didn't have time to make it last night. Not only did I have rehearsal I had to take Bea to her Tball practice as well. They were literally back to back. So I'm up making her lunch. Cutting her sandwich into a star, washing her grapes, getting her cookies etc. I threw it all in her lunch box and stuck it in the fridge. Good to go. During the course of the morning both girls woke up early, so I had them underfoot while I was trying to get ready. Surprisingly I was out the door at 7 a.m. with lunch box in hand. We even sat in a parking lot for a while because we were too early for daycare. After dropping Millie off, Bea and I hit the grocery store - she needed something more for breakfast before I took her to work with me. We grabbed some pop tarts, bread, etc. We get back into the car and Bea had been asking me for a fruit by the foot for a while. I had thrown one in her lunch box so I went to get it out. That's when I noticed it.
I forgot her damn juice box! FUCK! Are you kidding me!? I had all this time I could have easily thrown it in before we went out the door. Why didn't I throw it in!? Damnit! I didn't want to go back home just then because not only would I be late for work I'd have to deal with the damn traffic and I was SO not in the mood for that. Heck I'm still not in the mood for it. I'm just so furious at myself for forgetting something so simple! And more importantly I wasn't even in a hurry this morning I had tons of time!!!!! I could have easily picked something up while in the store... but I wasn't about to go back in... I just try so hard! And there are so many things I have to remember! I constantly have my phone's reminders chiming at me... fuck!!!!!