Spotting and hcg levels

On 11/11 I had 3 positive pregnancy tests! On 11/13 I started spotting brown. I've been spotting brown ever since. I went to my obgyn on 11/16 and they did an ultrasound (tv) but the baby is too small but my uterus lining is thick which indicates pregnancy. So they did an hcg level 11/16 and it was 50. They did another one 11/18 and its 110 and now they are doing another tomorrow. Are my hcg levels okay? Is the brown spotting a huge concern? I am worried. According to my period (not regular, 1st one in 4 years after Implanon) I am 5 weeks if I had a 28 day cycle. They think I may be earlier (ovulated later in my cycle). Any thoughts? Anyone? Please.....