Has anyone ever had a bad reaction to their MTX? If so, what happened??

I did my injection yesterday at 1000am. I was OK until about noon when it suddenly felt like I was being stabbed in my lower abdomen. Women, it was like menstrual cramps turned up to a billion!! I felt hot and then cold and then at one point, my body was cold but my head was hot and I was sweating in my head alone. Then came the diarrhea (bad). I felt weak, my chest felt tight. I started coughing the dry hacking barky-echo-y cough again ... I wake up this morning feeling intense pain again, more weakness, my lungs almost feel like they are burning when I breathe, my mouth feels perpetually dry .... and the diarrhea .... it's like a knife to my gut when it comes.
And then, my abdomen is tender even when the pain subsides. I lean forward and it feels full ... and so so so so so tender.
I don't know. It could be completely unrelated but then ... the spec sheet from my meds said to call the doctor immediately when I have certain symptoms. Which included the lethargy, the diarrhea, the weakness, etc.

Anyone else?? I'm gonna try and get in to see my family doc tomorrow. My rheumy said go see her first. I could have done that already.