Mobile network problem

Hi.

I had purchased a samsung galaxy y s5360 with android 2.3 installed by default. I came across the idea of overclocking the phone but had to root it and put a different rom on it. So i did without any problems. But it was very slow after that. So i decided to install another rom, which went all to plan, however now i have no reception. Its so bad i cannot ring emergency services. I have always had reception before this. I installed the default rom and still had no luck. But when i went into town i got reception and all my txtxs came through. its like it does not have enough voltage or something??? Pleeeeeeease help me