I've actually had the same thing happen to me though not when I was pregnant. I would get really dizzy but not really have any other major symptoms. Only a slight headache. When I look back on these times it happened when I was really, really stressed. I don't want you to take offence at this but in my case I think it was psychosomatic, it was at times when I was really busy. I think it was my mind's way of telling me that I needed to rest my body. What helped me was taking motrin and spending a couple of days in bed. I think it was rest that actually fixed it.
In terms of a pregnancy test I would bet your doctor already ran one with your blood work, it is usually the thing they try to rule out first. Whatever it is I hope you feel better soon.
I was super dizzy once. After a few weeks of putting up with it I went to the doctor and it turned out that one of the tiny bones in my ear was slightly dislodged. It went back into place on its own after a while and I just had to take some anti-dizziness pills until then which helped. It was a pretty cool thing to explain to people! Lol.
It might be different where you live, but in New Zealand pregnancy tests are not part of a standard blood count so if you'd had the test done here it would be very very unlikely they'd have looked at that - but like I said, might be different where you are.
If you have any reason at all to suspect you might be pregnant then take a test. Couple of dollars for peace of mind is worth it :)
Whether or not a pregnancy test was done on you really depends on your doc. Some docs include it routinely for all women in the child-bearing age period and some don't. But I'm sure you can call and ask. The most important thing to do - if it wasn't included - is to take a test yourself. Pee on a stick or go back to the doctor and get a blood test. It's not one of those things that goes away if you ignore it long enough (as you know). I've had bouts of vertigo and it sucks so you have my sympathy! Mine turned out to be related to a severe sinus infection. Hope you feel better soon!
Is you friend that type of people who think woman's poor health can be caused only by pregnancy or PMS? One of my friends is the same kind, she suspected me of being pregnant since teenage years, well.
Firstly, you should not worry or freak out because it's bad for health anyway and can make you feel only worse. I am pretty sure low platelets can be the reason of dizziness. Or it can be low air pressure, I feel dizzy very often if the pressure is below 730.
As for pregnancy, while it all depends much, my only pregnancy symptom was the absence of periods. No headaches or nausea.
Don't freak out yet and I hope you feel better as soon as possible. And if you are pregnant, I am sure you will be a great mommy ;) Surprise babies are gifts, believe me.