No text messages (in or out) on myTouch

[GadgetMomma]

I'm using an unlocked mytouch 3g slide on AT&T, and my text messages all of a sudden stopped working today. I unlocked the phone on Friday and got everything set up, and it was working fine, and then I've had several people tell me today that they've texted me and I haven't received those messages. So I've tried to send my husband text messages, and had him send me some, and nothing's coming in OR going out. Could the problem be a wrong APN or something I entered when I unlocked the phone? I really appreciate ANY help, because I'm a little dependent on my text messages - it's how I keep in touch with my husband when he's at work, and with my baby sitter when she has my kids, so I really need it to work - and work well, obviously. Any help would be appreciated! Thanks soo much.