Hcg levels

I got a few clearly positive tests so last night I took a digital with weeks estimation to see if my math was right and it said 2-3 weeks so I decided to double check it with fmu since I had just drank a bottle of water about an hour and a half prior to last night's test and this morning it said 1-2 weeks but the line on my cheapie was slightly darker than the fmu cheapie bfp I got 2 days ago. Should I be worried (I've miscarried before) or is the test probably wrong? I'm not sure how to ask my dr for a blood test before my 8 week check up. The doctor is amazing but the front office staff are completely incompetent and it took 2 times of me telling the lady I was pregnant and needed an appointment for her to even understand that they needed to schedule me for my 8 week appointment.