Period while being pregnant ?

I've had now three periods since I thought I was and I still feel pregnant . I didn't gain weight but my stomach looks bigger , I had all the symptoms even morning sickness . And even pains that I thought were round ligament pains and I would be 15 weeks . I haven't taken a test since a few days after my missed period in the beginning . Now my last period I just got off of it today and it only lasted 3 days that's weird . Has anyone ever had their period and was actually pregnant