I know what you mean April. My most recent was my 3rd. I have a daughter but because of that I wont get any tests as its not 3 in a row. Im so jealous and feel its so unfair that other people can just get pregnant, Sail through and have babies but I cant.
It was 3rd time lucky for me with my daughter too so never know. With future pregnancies Ill take a heartbeat with a pinch of salt though as Ive had one in both my missed miscarriages. I think a heartbeat along with appropriate size is the biggie, mine both measured small but thats just personal experience.
Good luck today. Youll be ok x