Is this in my head or should I be worried about a miscarriage?

I am 6 weeks 3 days pregnant. At 4 weeks 5 days I had a scan and they were able to see a sac in my uterus and my hcg levels were at 2000. Is this normal and good. The reason Im worried is because back in January I had an ectopic pregnancy and they removed my right tube and ovary. Does this put me at a higher risk for miscarriage??? I go back to the dr on June 1st for another scan, im terrified I wont see a heartbeat. I have had 2 healthy pregnancies before so I kinda know whats normal and whats not, but every twinge or cramp in my stomach just scares me. I do get real queasy and gag alot but havent vomited yet and my do ache but not as bad as my last pregnancies. I would be content to know this is all in my head but just need reurance. Thanks in advance!