In need of more opinions...

So, my boyfriend and I have been using the withdrawal method - I know I know, it’s not accurate and we should use another method too, I don’t need to hear it - and my period was due five days ago. I am having - and have been having - all of my usual period symptoms: cramping, diarrhea, sore boobs, appetite changes... the works. Just no blood. Annnd added pain in my one side - front and back - and way more intense nausea. The last time I took Plan B was in March, so that *shouldn’t* affect anything (right?). And another important detail may be I had an appendicitis scare and my doctor thought maybe it was a cyst - but to monitor in case it was appendicitis. Anyway. I took a test yesterday morning - negative. I didn’t completely trust it so I did it again this morning. Negative. Should I trust it? Wait a week and try again? Or could something else be going terribly wrong in there?

(Side note. I do have my annual check up in a little less than two weeks too, which is why I haven’t gone to the doctor yet)