Twitter

I'm having problems on my twitter on my iPhone. I can't seem to refresh my timeline, retweet or even tweet. Not too sure what's wrong. So I went in to my iPhone settings and then on to twitter. It said that my username or password is incorrect though I haven't changed any of them. I haven't had the chance to look on my laptop yet. I hope my account hasn't been deleted :(. Has anyone else had the same problem with twitter? X