My boyfriend and I have been sleeping with each other for over three months, however a few days ago sex became painful. I began experiencing a cramping feeling while he was inside and afterwards I would end up bleeding a lot. This has been the case for the last four days however, yesterday and today I've began to also experience nausea as well . When I was 19 I did catch chlamydia but I was given really strong antibiotics and have been STI free since. What could be causing these symptoms ? could I be pregnant or is this something else ?