I need some opinions has anyone gone through this??

so i got my first bfp at 12dpo!!! the day i was suppose to get my period tuesday june 5th 14dpo i started bleeding not enough to fill a pad but had lots of blood clots and was dark reddish brown for one day then yesterday and today there is still some light brown when i wipe anyways i went to the ER and they called it a threatned miscarriage and that my hcg level was at a 12.8 which is pretty low i have another appointment tomorrow morning for another blood draw. im pretty sure i ovulated on May 23rd anyways ive been taking test everyday to see if the lines were fading i never had a positive on a clearblue digital or first response digital untill today is that a good sign or not really is my hcg levels going up?? its been 48 hours since the blood draw could i not be miscarring?? has anyone been through this. and it come out good??