Went to the ER yesterday 😭

Yesterday my period cramps were so severe I went to the ER. It was awful. My son is 16 months old, I've been on the paraguard IUD for about 13 months and haven't had any issues, but because I was nursing I didn't get my regular period back untill about 3 months ago when I stopped breastfeeding. I was nervous about severe cramping because I heard that can be a side effect from paraguard but I hadn't had any issues the last two months with my post nursing periods. I decided to try one of those menstrual cups this month as well. Days 1-3 of my period were pretty normal, I had heavier bleeding than normal for me and intermittent cramping that sometimes was a little heavy but nothing I couldn't handle. Day 4, yesterday, was different. The first half of my day was normal, but around 2 pm my husband was driving us to the zoo and I started getting some intense cramps. As time went on they started getting worse, it felt like labor pains/contractions. I was nauseated, light headed. He stops to get me some Motrin, and I call my OB. They said to take the cup out, and if I'm soaking through a pad in an hour or less to go the ER. So we're on our way to the grocery to get pads and my husband pulls up and asks if I can manage to run in and he will circle the block- I say yes. I get out and I can feel a cramp starting. I got from the front door to the check out Lane and took and knee and slowly fell to the floor. I thought I was going to pass out from the cramp. A staff member helps me walk back to the car. I start crying- I have never felt this bad from my period. I tell my husband to take me to the ER. It was a 7 minute drive but I felt like it took forever. My cramps were getting worse- I'm not kidding when I say I feel like I was in labor again. My abdomen feels distended with lots of pressure. I'm starting to shake like I had body chills. They get me checked in. I stop getting cramps. I still feel nauseated and light headed. They do a pelvic exam and an ultrasound. Four hours later they come back and the results show nothing abnormal. For two hours today I had the worst period pain of my life and then it went away and now I feel fine. Like what the hell happened?? Not to mention I am on vacation right now so my poor husband and son spent four hours in the ER with me bless them. I'm scheduling an appointment with my OB when I get back. Has anyone had period pain like this? Do you think it's the paraguard? My body adjusting after stopping nursing? The menstrual cup? All of the above? Or the universe punishing me for being a woman?