I went down to 0 mg of nicotine in my e cigarettes due to headaches it was causing me. i have a huge appetite now. is this normal?

Yes: Increase in appetite is quite common after quitting smoking. The good news is that it usually goes back to normal. You may gain weight in the short term, but are not likely to have any long term weight gain. Congrats on quitting! it's the most important thing you could do for your health. Just don't pick it back up.

Nicotine: May work as appetite suppressant, eat smaller and more frequent meals. This shall pass.