dealing with my decision

Not sure how to start off this post but I guess I'll start by saying I have a three-year-old son and A 10 month old daughter and I had my tubes tied while giving birth by c-section to my daughter... I knew I didn't want any more children because my pregnancies were hard on me mentally and a little physically but honestly I had very healthy pregnancies I should not complain whatsoever to just my mental state that has a hard time dealing with my pregnancies ...so now I'm going through another rough patch another patch of pretty severe depression and one thing that bothers me is having my tubes tied and I don't know why it bothers me because honestly I could not deal with another child but knowing that I will not have another child hurts my soul ...it has turned me into somewhat of a bitter woman ...my sister-in-law is pregnant right now and I don't even really speak to her and ask her anything that has to deal with her pregnancy or anything like I'm almost jealous but why.