I have broken my word to myself.

I started a new job recently, having had a difficult time in my previous job I concluded my big personality and intense desire to be liked and to be considered funny and unique were not my friends then. Buiding from my previous experience I promised myself that on my new job I wouldn’t drink in social events with colleagues and would never make sex jokes or comments.
Few weeks in and I have already got a bit tipsy once and made a comment about my personal sex life (building from someone else’s comment something like ‘I’ve tried that and is not my thing).
I definitely should stop drinking altogether. I get really anxious when I drink and go into a full-blown paranoia mood. I try to convince myself that nothing said or done was that bad, and if someone was in my position I would really make an effort to show them there is nothing to worry about. I also suspect that if/when I stop drinking I would find reasons to be worried about anyways.
The thing is I also know there must be something behind this big personality thing, is it really me or is all this a strategy just to be liked.
I really need some help trying to figure where to start, on this and what I should be focusing on. How can I unearth the thoughts that are getting this results? and are there any suggestions where I should start from?