Marathon runner woke up with extreme nausea (vomitted) extreme stomach pain?

I just finished a half marathon two days ago. I’ve done several before and also a few marathons. Typically I’m sore and tired the days after but this time it’s different in that I have severe stomach pain. I felt fine immediately after the run (except for bloody stool). This is normal for me after long runs and went away within 6 hrs. I felt fine yesterday. Then this morning I woke up with extreme nausea (vomitted). But the worst part is the extreme stomach pain throughout my entire abdomen and stomach. It feels like I got kicked or punched all over it. And I have chills. Even despite a bowel movement, I’m still in a lot of pain (doubling over just trying to want to the bathroom). My question is what caused this? Could it just be my body isn’t handling the long runs anymore. However I had training for 3 months prior. Another thought was that it could be something I ate (food sensitivity). I typically feel very bloated if I eat gluten so I do avoid it. However for the race I had to carbo load. Could these symptoms be related to that? I just want to know what this could be and if it’s needed to go to the doctor?