Advice- Is this normal?

Hi, I've been TTC for a few months and my period was a day or two later then expected (I've always been a little irregular, around a 30-34 day cycle). I woke me up last night at 12:30am with rapidly intensifying cramps, something felt so wrong, it was so bad I thought I was going to pass out or die, I was in so much pain and was nauseous and felt my blood pressure change (going weak), I had to lay on the bathroom tile floor shivering and had my husband bring me cool rags for my forehead and ice cubes because I was so thirsty and he stayed with me until the Advil kicked in talking me through it. I felt like if I tried to sit up I'd throw up or pass out. Eventually I was able to transition back to the bed. This has happened in the past before (about 2-3x in the past 5 years) sometimes I do throw up, this time I didn't. It's so scary I worry I'm having a miss-carriage or something is really wrong inside. It's the worst experience, I seriously feel like I might pass out and die, my body just goes weak. The first time it happened I went to the ER they give me pain meds and about an hour or two after it begins I'm back to manageable cramps, it's the first hour that's so intense. It makes me worried is there something wrong with my body? It's not uncommon for me to get blood clots during my period. My doctor knows and we ran every sort of blood test and everything comes up fine. Has anyone else dealt with this sort of thing? I hate being weak/feeling weak but when I have episodes like this that I can't escape it's so scary.