Medication while Breastfeeding

I have fibromyalgia and other health problem as a result of a Car wreck when I was 15. I went off all my medication when I found out I was pregnant(so a very long and hard pregnancy) but the Doctors are putting me back on them as soon as I deliver. My question is.....I really want to breastfeed but I'm just wondering if the benefits out way the risk or if it would be better to just formula feed. My Doctors said it was completely up to me. Has anyone breastfed while on medication and what was your experience?   Gabapentin and Amitriptyline is what I will be taking.