So confused if this is a miscarriage

Posted here yesterday that I had bleeding in my 5th week it's not as heavy as a period bit I have cramps and backache and I went to the doc and my cervix was still closed and told me to rest...I couldn't sleep so decided to go for an ultrasound and i was made drink almost a litre of water ..the doc said he couldn't see anything and he was doubting if I was actually pregnant or maybe I was having a miscarriage. .he then took out a hpt and we took a test immediately and it was negative 😲😲😲😲I just had a hpt on Saturday it was positive am wondering how 2days later it's negative and the doctors aren't giving me any straight answers they say it might be too early to show up on an ultrasound or maybe I was miscarrying😣😣😣 am confused now and I'm relaying on other people's experience to know what am going through. .I've been told to wait a week or 2 for the bleeding to stop and go back for another ultrasound. This hasn't helped me in any way my next appointment is next week..what do I do...am too confused at the moment. .please don't get tired of my posts am just so desperate for some help