Low hcg levels and very confused

Okay so i have taken multiple hpt tests and they have all came back positive. I had my first ob appointment yesterday and when the did the urine tests they came back negative! I am so confused. They sent me for blood work and it came back with a beta level of 13.... So i grabbed a clearblue digital weeks estimator and again got a positive. I am so confused😞 i go tomorrow to have blood drawn again. Here is the test i took. Is it normal for my levels to be so low at about 4 weeks along?