PMS or EPS? 😒

Erica
So last month I spotted 7/23-7/27 a light pink and it got a little red on the third day and it went away.
I took a hpt and it was negative..
Wasn't sure if it was implantation of AF. So I took a test anyways. It was a bfn. So I assumed it was AF. 
I went to my obgyn 8/5 and he said everything was okay on the inside and said it was okay to ttc.
Well if that was AF I should be due next week..
But this morning I've been very nauseous and almost vomited but didn't. I've been really tired and crabby lately.. But that could be PMS. 
Any way my obgyn couldn't tell if I was pregnant at that time?
Or could I just be sick and this nausea is nothing? 😩