I'm so sorry, what a difficult position to be in. What I will say is that doctors are sometimes wrong. Giving yourself time before having surgery is ok! Get a 2nd and even third opinion. I agree with you in not wanting to just jump to conclusions about this pregnancy. One day at a time...
A close friend of mine had a similar experience...the doctor REALLY pushed her for a D&C, but she refused, (it was not ectopic just to clarify), but she waited it out. Went for her 12 week scan and sure enough there was a healthy baby with a heartbeat!
So doctors DO make mistakes.
It's good to trust your care provider and listen but sometimes that mommy instinct weighs out a doctors opinion.
If it IS ectopic it will be seen on an u/s around 6-7 weeks usually...but be aware of the dangers in leaving it too long. It's a bit of a balancing act for you right now, I get that. Not easy. Will be thinking of you and please keep us updated.