It is also completely normal and very very common. You are not alone.
Don't beat yourself up. In time you will reconcile with the notion that it wasn't meant to be. That's no use now though, time is raw and nothing anyone can say will repair that.
Relaxin, hormones etc ....yep, fine, good points. BUT if you want to run then you should. HOWEVER, if your body image is whacked then that's another issue....you owe it to yourself to get back in shape and strong for your baby, for there will be another one and you will be a cracking mum. You think you look odd? who gives a flying f#ck - you have the strength, you can do this, you think anyone smirking at your body in running gear has even half the strenght and courage you've got?
There is a time when the introspection must cease, and the building goes on. You'll know when that time is - don't rush.