Left with more questions than answers

I was on BC pills I took 2 rounds of antibiotics in August and my periods were on and off. I don't know my exact LMP however I took a pregnancy test on 9-17-15 was negative. Took another on 9-22-15 was positive then another on 9-25-15 another positive. 

I went in to my OB Tuesday took another and again a positive. He didn't do blood work nor a pap. He only did a U/S. He detected a cyst but no baby. No one ever told me about a cycad when I miscarried in April and they did I many many U/S. Can the Dr be missing something??  He said the chances of a etopic pregnancy was slim but never bothered to check. I am so confused. He scheduled me for another U/S in 2 weeks.  We asked if he can do a vaginal ultra sound he said no.