i've had lighter periods than usual and have been throwing up yellow sick (3 times) i have taken three tests- all showed negative.

I have pain in my stomach and white vigina discharge. I have also had a decrease in apetite. I am 5ft 6 and weigh 10.5
I last took a test three days ago.
The last time i had sex was 15 weeks ago.
What are the chances I could be preg?

thanks for ne help