1. Above all else... conserve what battery you have left on your phone.
2. Download your stock firmware onto PC and copy it onto external SD card using a USB reader.
3. Download Mobile Odin
4. Are you running Triangle Away
Back home soon!
Back now. My gut feeling is that it may be a hardware fault. See, here
. Either way, with limited battery, your first priority must be to get back to stock before trying anything else.