Jade,
Good luck with your new cycle. This is my second IVF. I did 2 IUI's and 1 IVF at another clinic here in Tampa. My experience there was not good, which is why we went to RMG. We have really liked how they take care of the whole process.
I took my HCG shot on the 15th, and tested the 28th, so it should be ok, but i understand it could still be in my system. I am not taking anything the HPT says as science. Actually, the line is so faint, that it probably doesn't mean anything, since it is an early one that can detect 20hcg. Who knows!!
I have another 5 days of waiting. The last time we did IVF i was "borderline", some term the other clinic used. I had a low HCG of like 13 or something like that. It went up over the course of the next week and I ended up miscarrying. I just pray it's either a BFP or BFN, nothing in between - I can't take the rollercoaster.