Your probably not going to like my advice,but it may be your only option. Hard Reset your phone!
This means you will lose all your apps and personal data,which you will have to set up all over again. I told you,you would not like my advice.
Pull battery then reinstall battery. Hold down home button+volume down button,then power button,all at the same time. Do this until you see the Android recovery screen.
You scroll up/down using the up/down volume buttons. You select an option by pressing the home button. Select the factory reset option.
It sound like you need to install your apps one at a time over the course of a few days to see which app is causing your system to crash. Giving plenty of time in between each install to determine which one is messing up your system. Also some apps don't function properly on the sd card and need to be moved back to the app partition on the phone.