4th Baby? Am I crazy???

So I just had my third little 6 weeks ago and I am already thinking I want another in the next couple of years. Am I crazy? Is 4 kids too many? Any mamas out there that have made the decision to have a big family like this that can give me positives and negatives? I have always wanted a big family but I’m worried maybe I’m being selfish. Obviously the more kids you have there more money you’ll spend on them. Right now we are comfortable but on a strict budget. I have a career and my husband stays home so we have to be pretty fragile to make it work. Any opinions are welcome! Pic of my adorable littles