iphone restarts every 2 minutes
It seems like your iOS software might be corrupted. I would suggest you to backup your iPhone through iTunes (no worries, iTunes doesn't detect whether your device is jailbroken) and restore your device to factory settings, restore from your backup and jailbreak again. If everything goes smoothly, try to be careful when adding sources or downloading apps and tweaks, because if you add untrusted sources, viruses might be downloaded and since file viewing is possible on a jailbroken device by users, viruses can too.

If you're afraid to lose your jailbreak settings and any configurations you have made or you have bought paid apps, I recommend you to backup all of your apps and tweaks by downloading OpenBackup via Cydia. I doubt you'll be able to do all that because the process of downloading and installing the app, and backing up the contents take more than 2 minutes. I was using iOS 5 when I was tempted to upgrade to iOS 6 and my iPhone was "bricked", so I had to give up my jailbreak and restored my iPhone (same as yours that time, iPhone 3GS). Few months later I bought an iPhone 4S and tried to jailbreak it and I was happy to realize that my jailbreak settings were still there! So I hope when you restore your iPhone and jailbreak again it will have all your jailbreak settings.

Hope this helps.