help—a mama needs advice!

ok, so my situation’s a little weird I found out I was pregnant March 7. That was when I got my first positive pregnancy test my expected period was supposed to start March 1. Mind you I have a one year-old daughter that I just quit breast-feeding the second week of February. My period app told me I ovulated February 16, but I’m thinking since I quit breast-feeding it made me ovulate a little bit later than that mind. You i also have a history of not so good pregnancies so I went in to get checked March 10 and my hCG levels were at 91. They had me follow up Thursday (March 13th and that morning at 11 they were 255. They sent me in for a transvaginal ultrasound and couldn’t see anything and wanted me to follow back up yesterday to have them re-checked before leaving the hospital Thursday (March 13th) I was there until about eight. They rechecked my levels at 6 PM and they had already went up to 373.1. Yesterday my hCG levels had risen to 520. My question is they gave me another ultrasound yesterday and still couldn’t see anything am I probably still just super early and do my hCG levels sound like they’re progressing good ?