I had unprotected sex on 4/10/17 with an acquaintance, but his sexual history is unknown. I went to an OBGYN on 4/26 to get tested for any sexually transmitted infections (this included a 4th gen HIV test). All tests came back negative. A few days ago, I had severe bloating, abdominal pain, cramping, pelvic pressure and frequent urination. Those symptoms have gotten less intense, however I still have them. Now, I have pelvic pain and noticed that the lymph nodes in my groin are very swollen and I feel burning and pressure in them. What could cause this? Should I get tested for any STI's again?