Oh, I am so sorry. I cried reading your post. I went through a similar situation with my kitty Kasey, and you just never recover from that. We are here for you, whatever support you need.
Just draw your strength now from the fact that you were a loving mom and did the right thing by your darling Pita......that was the only thing that got me through, knowing I did what was best for Kasey. It still helps me, when I am missing her.....that part never goes away.
Sending special prayers your way today.....