Dear MadHamlet,

I can relate somewhat.
Know you are not your emotions, your emotions do not control you.
First on how to deal without upsetting other people around you.
Do not be reactive to these emotions when around people, tell your self I am aware of the arising and will resolve latter.

Chart your day/night and find out when these negative feelings begin and make a note of time/place/who.
These are not long notes just mark the time of day or night.
Where you are (work, home, car, in a store, out in public)
And who you are with. You can name a person but it is the character or action of said person that is more important.
Example Sara is a manipulator. So just note Sara/manipulative. Joe may be angry person ect.
And with just one word how this person make you feel emotionally. anger, fear, anxious, sad, scared, ect.
Chart for a week or untill you can see a pattern and work with that.
Even just noting time and emotion will help.