anyone else have a hard time singing live?

I sound good to myself, in my room, etc, but during live shows, my voice seems more muffled, strained, not as clear, etc.  I think, with all the extra noise and having to focus on playing guitar as well, I might just have too much to focus on.   Anyone else have trouble with this?  What are some tips for live singing, especially hitting high notes?

It isn't easy to sing and play guitar at the same time.  Do you practice that way?

It helps to sing TO the audience, make contact, "speak" to them. You might even sing better that way than in your house. It may not be technically better but emotionally more interesting and valuable. 

One thing I do that helps me (whether it works for you I can't say) is I look in the audience for people who look friendly and open and I sort of sing for them in particular. Takes some of the nerves away in my case.

Good luck!

I do my warm ups mid afternoon, then load/setup, then sing in the evening then I can hit all the notes I need. Without a warm up I run into the danger of straining my voice during the early part of the gig. I play guitar and sing 80% of the songs.