Two or three kids?

So I'm 37 this year, and I just had my second daughter, who has been so easy, but the new-born stage was horrible, with me having a reaction to the endone and having massive panic attacks and anxiety. She is now three months old, and I feel we are finding our feet again. We have had my partner's mum to help, as she has come from over the seas to help. The thing is, I'm sad I didn't get to have any boys, but I'm so thankful to have girls, as that was always a dream. I never thought I would have this sad feeling that I didn't get to have a boy. I'm thinking, should I try for another one in a year? It's so hard mentally to have kids, and I'm going to be sending them to a private school, which will be expensive. So I don't even know if, financially, we can handle having three. Is it normal to have these feelings, and I think I will regret it if I don't have another kid? I also had gestational diabetes during my pregnancy. Sorry if this seems like I'm rambling on; I just wanted to see what other people think.