Hi I'm 19 years old . About 3-4 months ago I had a ovary cyst surgery to have a cyst removed off my ovaries. About a month ago I had sex two days in a row ;unprotected, & just last week I had a 3 day period which I have never had before. I have been having excessive headaches, side pains, back pains, & my knees hurt from time to time . Could I be pregnant ? Or could it be something more serious ? I have taken a home test which came out negative but still are experiencing these symptoms daily .

Could be a complication from the surgery, could be something different. I would talk to your doctor about your symptoms. if you miss your next period that is when I would take a pregnancy test.