The reason your doc is checking for ectopic is that when you get pregnant on the pill or minipill you have a higher chance of having an ectopic. That's because both pills are supposed to change the CM which of course can cause delays in movement which can theoretically result in an ectopic. Even so, most women who get pregnant on the pill don't have an ectopic, it's still really rare for that to happen, just more likely than if you weren't on it.

Often with ectopics the HCG doesn't rise - that's why some women with ectopics don't even test positive on a HPT. Yours is raising as it should be so I'm sure all will be fine.

Congrats. It must be quite a shock.