ttc, 16dpo, severe nausea??

I am 16dpo and still getting negative tests. AF due today but not here yet. I have had cramps since around 6-7dpo that have now progressed into more like AF cramps so I was getting discouraged. I got so nauseous today around 11 that I actually had to lay down and nap for about 30 minutes to make it go away and have felt crappy since - I have had random dizzy spells which I blamed on symptom spotting but how I felt today was a first for me. If I were actually pregnant, wouldn't I have a positive test by now?! I know that I'm not out until AF shows but just curious for some input for those who have maybe experienced the same? Trying to hold onto any little hope I may have left.