ive been on them for about 3 months
If you're on birth control pills and also using other protection then no, you're not pregnant. You would have had to miss several pills and had a condom failure for there to be a chance of pregnancy.
Yes, it could be your pills making you sick. How long have you been on them?
If these symptoms keep up you should see your Dr to find out if you're sick because of the flu, a virus or your pills.If it's because of your pills then no worries, there are several others to choose from if you need to make a change.