Surgery

I have the opportunity to get a ban on my stomach but my problem is I dont want to do it if I have a chance of getting pregnant again so I'm thinking about getting my tubes tied too. I have a girl (4) and a boy (8m). I've always wanted 3 kids but financially it wouldn't be fair to have a 3rd. I don't know what is the right thing for me to do. If I get the surgeries I will feel better and have the energy to play with my kids but then I wont have any more. What would you do???????