I have had my iphone 5 since december and today it keeps losing signal and 3G, any help?

I have an apple iPhone 5, and I only got it in December 2012. Throught the day my phone has lost its signal connection various times - and i have checked there is no fault with the company EE, and it also along with the signal, keeps losing its 3G. This is very impractical for me as I need my phone throughout the day for work and various other reasons. Any help would be much appreciated! 🙂