Speak to your manager and ask them for support / mentoring etc.
Take time out at the end of the day to write down everything you need to do the next day / would otherwise think about. Take time to write what strategies you need to cope with each situation. Try to "leave them at work".
Before you have a confrontation, set out what you need to achieve, what you want to get across, what you are willing to give up, what could happen if you "fail" and what you would do about it.
See how you did against your plan after each one. Get in, get your point across and get out.
If you need to get out of a difficult situation quickly, at the start of the discussion say that you are due somewhere, need to make a phone call etc in say 5 minutes, and then when time is up, politely say that you are sorry but will need to take this up at another time.
When at home, keep a notebook so you can write down what you are worried about and what your plan is, even if it is, ignore! Then try to "shelve" the issue.
Remember it is "just" a job and the world is unlikely to stop if you don't do a perfect job every day!