ok, i feel like a fool to ask this question, and it's kind of gross, but i am supposed to have day 3 blood testing, what is officially day one of your period? i only have signs of period when i pee, otherwise there is no "flow" happening yet...so is this day one??

i am seriously confused over this, first time in my life (39) and probably bc i am heading into IVF for first time, so excuse me as i don't want to screw this up, but i don't need to use anything for protection, but when i urinate, i see blood, i would call clinic but of course it's the weekend and i am away right now.