Possibly my 4th MC...

So my story is a little unusual, or maybe not....

I have had 2 BO (12/16-4/17) and (9/17-2/18). My second m/c lasted from 1/24/18-2/7/18. I had another bleeding cycle 2/20, when I normally have my cycle. I was supposed to ovulate around 3/5. My DH baby danced on 3/3 and 3/4. On 3/8, I left for two weeks to care for my father who was put on hospice for colon cancer. He passed away on Monday 3/19 and I returned home that day. Knowing I was supposed to have AF on 3/20, I took a PT and it was VERY faint positive. A few more tests within the next few days showed just as faint, if not fainter. We baby danced on 3/23. I waited until Sunday 3/25 to repeat test. It was pretty much negative. A barely faint line showed up the next day, as did the cramping and bleeding. After only 4 days of heavy bleeding, it stopped. I assumed I had a CP and threw all my tests away and stopped testing. My DH and I baby danced on 3/29. On 4/6 I took a test because of very tender breasts and extreme fatigue. BIG FAT positive where test line was darker than control line?!!!

I made appt with OB last Tues 4/17. She sent me out for titers and US. US revealed NO intrauterine pregnancy. Titers on 4/17 were 5000 and on 4/19 were 5500. They gave me results on 4/20 and told me my levels were rising but to call them if I have any bleeding or spotting. They didn't give me any more info than that and scheduled me to come back in 2 weeks.

I have another OB appt tomorrow with a second doctor as I need to switch OBs and am supposed to have another US... after everything I read online,it looks like I am at risk for an ectopic pregnancy since I have slow rising hCG levels. Also everything I've read has indicated that with hCG levels of 5000 you should see something on U/S. is it possible I'm just very early and this is a viable pregnancy, or am I right to worry and get a second opinion?

Thank you for reading my post!