Someone please HELP!!!

Ok so my last period was on january 12th I found out I was pregnant February 12th. On March 1st I woke up to bleeding went to the er and my levels were only at 400 which is very low I bleed for a week like a normal period. I had an ultrasound done and they said they see nothing but that it may be too early. I do not feel pregnant. Well today I went to the doctor and he told me nothing indicates that I’m not pregnant he took my levels and sent me home I will find out tomorrow we’ll now I’m sitting here going crazy! I decided to take a pregnancy test well it’s positive and the second line is very dark! I’m so confused has anyone been through something like this?