Quite honestly, if you can manage it from a funding perspective to go to med school after you have already studied law (and presumably a first degree as well, as you talk about JD), go for it.
My perspective will be a bit different because I did not originally study in the US, but it's still strangely similar:
1. Pre-diagnosis, when I was 18, I moved from Austria to Switzerland to study technical physics at the ETH Zurich. In the first year at university, I was diagnosed with Crohn's and was in pretty bad shape. Along with the stress from studying quite a hard subject at a top school, plus Crohn's, plus being in another country, I decided to come back to Austria.
2. But the technical university in Vienna is two notches below the ETH Zurich and I wasn't thrilled anyway to continue physics. So I decided what the heck, I got Crohn's, what better thing to do than study medicine (it's a minimum 6 year degree in Austria, but no need for a first pre-med degree). I aced my first exams and generally liked it, but - well - three of my fingers on my left hand (all except my thumb and my pinky finger) were affected by an amniotic band constriction that entrapped my left hand during the later part of when my mother was pregnant. It doesn't affect me one bit, I play the piano and write rather fast on a computer. Anyway, during anatomy classes when we worked on bodies, I realized that one of the problems down the line would be sterile glothes. Of course it's possible to wear them, but in the surgerical field that might just have posed big problems. It wasn't the only reason I switched study fields a second time, but anyway, I still abandoned medicine back then.
3. I switched to law (again, just like medicine, it is a first degree in Austria as it is the case in most of Europe) and studied computer engineering in parallel and graduated both. Later on, I moved to NY and studied at NYU for an LLM and have since then (with a few years doing other stuff in between) worked as a US and eventuall German lawyer (also passed the German bar).
Soooo, long story short, I believe, if Crohn's wasn't a problem to get your JD, it won't be a problem to get your MD .... all provided that you actually have it under control right now and know how to manage it. The only problem I could see is if you really want to go into dentristy or surgery. Those jobs go along with many, many hours of "standing around" while performing surgery, which can be quite strenuous. I was interning in cardiac surgery for a month between terms when I studied medicine - as first year students we weren't allowed to much at all, but we were allowed to observe in surgery from the side and believe me, you really need to be able to stand for many long hours each day.