I think ectopics tend to have big increases in HPT early on before dropping off around 6/7 weeks. But if you are concerned, you should see your doctor.

Which tests did you use? If they were different brands they could have different sensitivity. Or even the same brand from different batches can have differing sensitivities. Check out this link: POAS ~ HPT FAQ You might find some answers to your questions there.

Good luck. Keeping my for you.