pregnant with low hcg levels

so I found out im pregnant! but they checked my hcg levels.On Wednesday they were 77 and i started getting pain on my right side.I went to the hospital and they checked my levels again they were at 317 ! ( this was Saturday ) they are still very low , il be going to get my levels check every two days in hope that they are rising! they did a ultrasound to search for a ectopic pregnancy and couldn't seethe pregnancy yet they think I'm to early ! but I'm supper scared now ! has this happened to anyone ? please share storys !!!!