I changed jobs not too long ago due to my former company shutting down my division so I totally get New Job Anxiety. I am not a social person by nature so having to establish new working relationships sucks. But, as you said, nothing is permanent including feeling awkward.

What helps me is to remember the eight worldly winds; praise and blame (or awkwardness and confidence) happens to everyone and it's fine to feel off in a new environment. Here's the sutta in question: www.accesstoinsight.org/tipitaka/an/an08/an08.006.than.html

Incidently, I find that it's the people who AREN'T super confident and have some self doubt that are the best employees because a) they listen and b) they tend to pay better attention to what they're doing because they don't want to muck it up.