5w5d and spotting- tmi

I am 5w5d and started spotting this morning. They drew my beta and it has more than doubled since Thursday, but I am really worried. It was bright red blood and then later it was almost a bloody mucus and I passed two small pieces of tissue. It wasn't blood clots and I wouldn't consider it active bleeding because I haven't had to change my pantyliner- it's just when I wipe. My RE put me on bedrest until the bleeding stops.. does anyone have experience with this?? I have an u/s tomorrow morning.