Why is my ultrasound so fuzzy?

I had an ultrasound yesterday. I thought I was 7 weeks but I’m actually 6 weeks. We could see baby’s heartbeat but couldn’t hear it. I’ve had miscarriages in the past. I have a 16 month old daughter who we conceived on clomid. I’m wondering if this pregnancy is going to stick. I’ve been spotting (which I know can be normal) and the sak doesn’t seem to be as defined as it was with my daughter. I also thought it was strange we couldn’t hear the heartbeat but we could see it. When I was 6 weeks 4 days with my daughter we were able to hear the heartbeat. I go back in two weeks but was wondering if anyone has any feedback on my ultrasound pic. Thanks.