PLEASE HELP my phones not receive my girlfriends texts!?

So i was texting m girlfriend earlier this morning and all was going fne.. then outta nowhere she stopped replying.. so i sent a few more texts b4 church in hopes shed reply but she didnt. so after church i checked my phone and still nothing. but then she messaged me on facebook freakin out wondering if i had received her texts and i was like.. no? and so she caled me just fine and asked if i had been receiving them and i still wasnt. so i had her send one while we're on the phone and i didnt get them. A little while ago she sent me a pic and i got it just fine. She receives mines fine which explains why she was freaking out earlier.. i just dont get hers. And if it helps i have Sprint and a LG Optimus, and she has T-Mobile and a blackberry(the one without the ball u roll)