Pregnant and Bleeding

I’m around 5-6weeks and I’ve been bleeding on and off for couple of days now. My first bleeding lasted one night and was a darker pinkish brown followed by darker spotting toward the end of it. I stopped bleeding for a few days and couple of nights ago, I started bleeding again but now the blood is a rust color and sometimes looks like coffee grinds (no clots). I’ve already had an ultrasound with a confirmed gestational sac and yolk but no fetal pole yet as I may be too early. My HCG level has gone from 18,924 to 66,201 in the last week so that is a good sign, I have another blood test tomorrow and another US scheduled next week. I am not cramping heavily which is also a good sign but I am still freaking out about the bleeding. Anybody have been through the same situation that ended up with a healthy baby? Or am I right to be concerned?