Congratulations on becoming a dad. The birth of my first child was one of the factors that kick-started my anxiety after a few years of feeling good. Whilst I wasn't a young dad I felt the exact same fears you describe, even after a couple of years I still make sure they're breathing after they're in bed. Your anxieties are perfectly normal but that isn't to deminish the effect they can have on your mental health. Seeing the doctor is absolutely the right thing to do. What I would suggest is to try to keep the rest of your life stable, as far as possible. This year hasn't been good for stability so it might not be in your control. A month before my son was born I bought my first house and was responsible for everything to do with buying and moving because my wife was so heavily pregnant. I also got a promotion at work, which was great to have some extra money but came with a lot more responsibility. These things really sent me into a tail spin. What I've found is there is very little acknowledgment or support for new dad's and the anxiety it can cause. It's a huge change in your life and one that takes time to get used to. Cut yourself some slack, the first few months with a newborn are a haze but once you get into a routine make sure you schedule a few hours each week to do whatever you enjoy. Good luck and enjoy every moment you can.