Dont worry, I have played many gigs and I still look like a dufus most of the time. Stage presence is not my strong point, especially at non-drinking type gigs!

. I used to be an eye-closer, but after getting ribbed for that from bandmates I have mostly fixed that bad habit. I also used to be called floppy fingers (bad technique)when I first started to jam with these guys back in the 90's! Some Bach studies permanently fixed that.
Luckily, I'm an ok player and they leave me alone now. Plus, there aren't many dedicated bass players round here.
Anyway, as long as you keep the time and add some groove, you'll be fine!