to be honest i dont think you *need* a reason not to have another baby. If you dont feel you are ready or that you want one that is good enough. and all of your reasons sound pretty valid to me. its not selfish that you dont want to be in pain or be fat for the rest of your life (byt he way i dont know if youa re fat or not just using your words lol) they are very valid reason and they are also issues that would contribute to your other kiddies. The getting on with your life bt might seem selfish but everyone has got to do it sometime!
anyway thats just MHO lol