Gonna be blunt here my dude, but it's an MMO. Even for one like this, it's expected that you play with other people from time to time.

And as one other person said, most people won't even remember you 5 minutes after the instance ends unless you do something that's like deliberately obnoxious. Just go in, do your rotation, beat up bad guys, get out. Very few fights in MSQ are very hard, they are designed to be cleared in a few pulls tops when new, when they are old most players already know them by heart and are heavily overgeared.

Just take a deep breath and do it. Worst case scenario is you die a few times, but believe me, nobody will care if you are doing your best (and if they do, they are an uncommon asshole).