Is it possible..

So I'm usually very regular, medium flow for 4-5 days. My period this month was a few days late and only lasted 2 days with brown/pink spotting before the blood flow.
​Now, since about a week before my period was due I've been quite unwell. Dizzy, nausea, acid reflux, bloating and uterine pain. I am currently signed off from work for dizzy spells, as i work in the community so drive a lot. I have taken pregnancy tests (pre and post bleeding) and all have been negative. Could it still be possible that I'm pregnant? I did a test today 1.5 weeks post bleeding and it was negative.
​Sorry for going on a bit, and thanks in advance for your help x