Hi Andreas
Stage fright was also a problem for me, one way to combat it is to sit in with a resisdent band in a open mic night, you are not exposing youself to anyone, but only one of a number of musicians (they have to be up for it though, you might have to prove it to them, that you are good enough)
Once you have their confidenc ein you will grow, and the familiarity of the venue will grow, and you'll feel comfy, the regulars will know you, and as
@Boydie says, all they want is to sell beer, and most of the people that turn up to listen only want to drink it, and listen a bit, and watch the match.
Good luck Andreas, just don't think of it as the Wembley arena with 10k people.
Let you music speak for itself, ask yourself, could they do it any better?
Hope this helps
Rich