18 days late

I am on cycle day 45 and I am 18 days late for my period. I have taken multiple(pee tests) pregnancy tests at home and 1 at the doctor all were negative... it’s been about 3 days since the last test I took. I have a appointment next week for a blood test but I just can’t wait!!! I want to know what’s going on I’ve never missed a period ever! I am not on birth control or anything either. What is happening? I’m pretty sure I ovulated this month. And a few days ago I was having sticky clear discharge but it’s gone away. I also have been super gassy and I’ve been skipping dinner every night for 3 days. Idk why I just haven’t been hungry around dinner time. I’ve been peeing very often.