Please Help.. Desperate Miscarry #3???

As an ob gyn for thirty years I have had a couple of women have a drop and continue to rise and have a healthy pregnancy. You can't goby symptoms they are not always the same pregnancy to pregnancy. And YES labs do make mistakes. In the past month and a half we have had two patients have negative beta hcgs and be pregnant. one had a positive home test and a positive one in our office and a negative bolood test which was positive the next day. We even had some one have a negative beta hcg with a heartbeat on ultrasound . It was repeated the next day an was 38000!