Phone gone crazy

Question

My sony ericsson 580i was working fine before going to bed last night. I wake up this moring and it has gone crazy, e.g I try to write a text message and it types all kinds of crazy letters by itself e.g. defdef. The same happens when I type numbers. Even when I leave the phone alone goes to sleep then suddenly it springs to life all by itself and types endless 888888888888's in the call menu. Is my phone fried???