Imessage is making me want to throw up.

My Apple ID was connected to my younger brothers iPod. when I used imessage he would sometimes get the "text" on his ipod. I signed him out of my account and onto my mothers Apple ID, but when I did that my imessage stopped working. I updated my Iphone 4 and when I went to sign into my apple ID to imessage, facetime ect. it wont work. I'm so confused and frustrated if someone could judt tell me what to do that would be incredible!

-Macey