It's not a "rough surgery" but you do run a risk of infection with it over time, especially as much trouble as you're having already. I have terribly "rolly" veins, have had mine blown many times and have had to sit through multiple sticks before getting a good spot. I know it gets painful, but they can apply a topical anesthetic (lidocaine) when sticking you.
I had enough trouble keeping my baby from pulling my hair (had to cut it) and earrings that I don't think it would have worked for me when she was a baby. I think your doctor is reasonable in his being leary.
Are you asking, is having another baby with all that's going on too risky? As sick as you have been, my advice (which isn't worth anything
) as a former infertility patient and mother of an only child is this: enjoy this baby you have and take the best of care of yourself so you can be there for him/her. The decision to have another child can be addressed later on. I know raising a child (who also has a chronic illness) while having CD is one of the hardest things I ever did.
I hope your health improves. -Joy