Ive fixed the problem but im worried that it might happen again...
This is what happened after I did the following
Updated to 2.2, install flash, update.zip for root, update.zip for 1250mhz kernel, and then updated baseband.
The phone was fine the whole night while plugged to the charger. I had the battery charged to 90%... So i just left the phone on my table and went off to do other things. Came back an hour later and the phone went down to 20%....! I was like what the hell.... so i went to charge the phone again back to 100%. Now it was all fine, so I went to work. And guess what, within 20 mins it went from 100% to 20% again... 10 mins later it went to 5% and died. Two full charges going down in less than two hours.
I tried rolling back with all my backups... did everything you can imagine to fix it. And every rom I tried to back track to was buggy... Some I couldn't get past the bootscreen, endless reboot over and over, and when I get past the lockscreen for some roms it would crash.
Then I finally decided to use Rom Manager and flashed CyanMod rom and everything went back to normal.
But really... can a rom cause all that problem?