HELP! I am supper congested and don't know what to do...?

I just moved back from Hawaii to California and have been seriously congested since I got here...4 weeks ago. I'm not sure why and I know I'm not sick. Lately I have developed alot of food allergies I never had and such...and am wondering if other allergies may have developed. Now I am always blowing my nose and always have mucous stuck in my throat. Any suggestions or ideas? I'd go to the doctor, but I don't have any medical insurance.