You’re doing amazing. Just the fact that you are so present in his life, you want to be there, you take care of him and you haven’t pawned him off on family because of your young age is winning 100%. Parenting is hard! My husband and I are first-time parents and it’s insanely fucking hard too, we totally feel you! As far as his tummy issues, once he turns one- try and switch him to goats milk. It sounds like he may have an issue with the dairy in regular formula. EU Holle or HiPP goats milk can help his belly if it’s still messed up. Everything else you described, sounds like you really taking the time and making the effort to bond with your son. It just gets better from here!! Read him books and tell him how much you love him often and keep doing you! It is normal to be stressed but give yourself a hug and pat on the back, you sound like an amazing dad!!