What Causes Abdominal Cramps Along With Nausea?

I have quite a bit going on right now. It began a few weeks ago, I developed sharp, abdominal cramping. I also had nausea along with it, but no vomiting. I was also experiencing migraines multiple times a day. We went to the ER and they did a pregnancy test which was negative, but also did a CT scan which showed several swollen lymph nodes scattered throughout my abdomen and then found one in my armpit. I have had lower back pain, shortness of breath, chest pains. This all lasted for a few weeks. Now, this morning I woke up with a swollen throat, stuffy nose and head congestion. I also developed a rash on my right forearm. Also, I have had some bloody discharge which does not match my period (which I have not had yet this month but all pregnancy tests are negative)