Wow that really sounds bad. My wife and I both have this phone and love it. The battery life isn't great, but thats to be expected with a 'pocket computer'. At one point I did have the problem where it would clear the To: field in SMS after typing a couple of letters of the contact's name. That's fixed since updating to Gingerbread at the T-Mobile store.
Maybe you installed a bad app? Try doing a factory rest and don't add any apps for a couple of days, see if that cures your issues. Or take it to a T-Mobile store and update to Gingerbread (call first, not all stores have the SD card to do the update).