You should do the check before you install...but in your case might be tough. I don't think I remember a time when md5 didn't check out so you're relatively safe. If you have a nandroid backup it would certainly help get you back.
Just reflash but make sure you WIPE DATA AND DALVIK.
Alright I will try it. I will flash the rom boot up and then go to flash gapps. You said you flashed kejar gapps what if I also did that? Would that be at all helpful? Where did you get it from? Thanks again for helping me out.