So my daughter is 3 years old and we are pretty much at the tail end of potty training. Our only real hang up is that she is speech delayed (which she goes to therapy for) so she doesn't tell us when she needs to go pee, we take her to the potty every 45 minutes to an hour and she pees on the potty and when she has to do #2 she normally points to her belly and pulls us towards the bathroom. So that being said, going back to her peeing, if we happen to take her and she doesn't need to go she doesn't tell us no or shake her head in any way rather she gets super upset to the point where we will have a 30 plus minute tantrum which involves her running back to the bathroom multiple times hopping on the toilet and hitting her private area because she is so mad that she doesn't have to go. This started about 2 months ago and I have no idea where it came from. Her dad and I have been trying to be sympathetic letting her know that sometimes you don't have to go and that's alright but she still has these meltdowns. I'd say they happen maybe 2 to 3 times a week and up until last night we actually had not had one in a while. I'm going to talk with her therapist about this but I won't see her until next week and I thought someone on her might have some insight or dealt with a similar issue.

Re: Potty Training - Weird Problem
So, tell her that sometimes we just try to potty to make sure we don't have to go, especially before meals, before leaving the house, before bed. You try. If you don't go, say "all done" when you're done trying and chalk it up as a win.
I'm not sure if I'm completely addressing your concern. I would also recommend being sure there is no medical issue causing the crying and repeat trips to the potty.
Also, it sort of sounds like you are potty trained more so than she is. Does she tell you when she needs to pee? You can also easily teach the sign language for potty and poop. If she only pees when you take her to the potty based on clock watching, then she is not potty trained.
My daughter gets really upset if we insist on her going on the potty when she doesn't really need to go. I also agree with the PP about teaching her sign language so she can tell you when she's ready.
At 3 she should be able to go by herself without you taking her. The way we had success with my DD PTing when she was 26 months was to tell her that she knew what to do and it was up to her. And to call us when she needs help (I would assume your DD can say something, if not I would just tell her we would come in after a minute to help).
Agree that 45 min. at this age is excessive. My DD often goes 3-4 hours between potty trips.