Guilty feelings...

So my daughter is 7.5 months old... I exclusively pump for her. She's fed breast milk all day. Her last bottle of the day is formula... I'm exhausted. I pump at 630pm and then I go to bed as soon as I put my daughter to bed at 8... Then I have to get up again and pump at 1130pm... Then back to sleep at midnight and I wake up to pump and get ready for work at 5am. Work starts at 6am... If it wasn't for that midnight pump I would feel better. I've been thinking about stopping the pumping and switching over to all formula but every time I think about it I feel so guilty!!! I only plan to pump until she's a year old so what's another 4.5 months after doing 7.5 already... I think it's just catching up with me. But then I also think that's selfish of me... I can provide (in my opinion only) what I think is best for her and I'm going to stop because I'm tired. "Welcome to motherhood" is what I keep saying... How do I stop feeling guilty... Sorry for the rant...