Just testing too early?

At my OBGYN appointment yesterday, they took a urine sample (no blood) and said it was negative. I've gotten 5 very faint (but clearly pink) lines on HPTs that show up within the time limit of the tests, and have a ton of pregnancy symptoms. She gave me a medication to start my period within two weeks, but it's not safe if I'm pregnant, in addition to BC. I'm supposed to go back if I don't get my period. I'm afraid to take the medication I'm supposed to get an ultrasound of my pelvis Thursday because she couldn't feel one of my ovaries. Do I just wait and ask them to check and see if they can see anything? I'm about 15 DPO and the last time I had unprotected sex was 16 days ago if that helps any. Anyone else have a similar situation and end up being pregnant? I've heard of some women who take until at least 19 DPO to get a BFP and some who only get it confirmed through a blood test.