Very nervous about bubs arrival

So I've been advised that I will be having a c-section for my bub due to current medical conditions and I'm very nervous about this for to the fact that I have a very low pain thrash hold and pain meds don't last long in my system unfortunately.
I recently had a laparoscopy bowel surgery in July and was on a pca for minimum 4 days. I understand that anything that goes in my body will then get transferred to bub through my milk and I just want to know what happens in situations like this?? 
Sorry if I sound paranoid I'm just really worried