Help something weird is going on...

So I know that it's impossible for me to be pregnant, but I need help. So here goes... I have endometriosis, this could be a factor so I thought I'd better mention it... So yeah I have noticed over the last two weeks or so that my stomach has got bigger, I feel movement in my stomach too and others can feel it also, it's not gas either. My endo pain has increased and I'm having severe headaches hot flushes and sickness. Does anyone know what this could be? Has anyone else experienced this? I know I sound stupid but if I didn't know that it was impossible to be, I would swear I was pregnant. Please help?