Bleeding & Low Hcg at 6weeks

This is my 3rd pregnancy. I've been tracking my periods and logging intercourse. My cycles are 28 days on average & 6 days long. I had sex 5/25/19 & 5/26/19. I was due for my period 6/9/19. I had a + hpt on 6/12/19. My pcm confirmed with another + urine test 6/15/19.

On 6/20/19 I had light pink spotting only when I wiped. No pain no cramping. Then yesterday (6/25/19) I had lower back pain mild cramping and started bleeding. The bleeding was only when I wiped never filled a pad maybe a drop of that. I went to the ER and had another + urine test. But my hcg levels were only 190 which is more like 2-3 week range. I had an ultrasound that showed a sac but nothing else. They said it could be too early to see anything else (as I am not as far along as I thought) or they said it could be a miscarriage. Still bleeding today but no backpain or cramps thus far.

My 1st OB appt is scheduled for Fri 6/28/19 and I'm suppose to have my levels rechecked. I know the reality is that this is more than likely not a viable pregnancy. I'm 37 and and we've tried for 1 1/2 years. I can accept whatever this is good or bad I just hate this limbo. I've never experienced this before.