One of my favourite things that my therapist has told me so far, which I remind myself of every chance that I get, is this: our brains are only trying to help us. We shouldn't be angry at them for making us feel anxious or angry or emotional or tired or lonely or confused. These are responses that would've helped us if we weren't living in a civilization. Instead of being angry at our brain or thinking there's something wrong with it, we should, first, acknowledge that these are very normal human emotions that we're feeling - we're not feeling anything unique. In fact, it's likely that most people have at one time or another felt exactly how we're feeling right now, no matter how confusing the feeling may seem and no matter how difficult it may be to put into words.
Second, we should try to understand what our brains could be trying to tell us and how they could be trying to help us. Things are almost never what they appear to be on the surface. If you started crying because your coffee order was wrong, the crying likely has nothing to do with the coffee. Your brain wants you to pay attention to something. Try to figure it out what that is.
Third, we should look at our situation the way we would look at it if it was that of a loved one's. How would we respond to them? Would we be as hard on them as we are on ourselves, or would we be patient and kind towards them when they're vulnerable?
Fourth, we should ask ourselves what it is that we need right now. Do we need sleep? Companionship? Distraction? Water? To just sit there and do nothing? To get back to work? We should try to find what it is that we need and how to get it. If we can't figure out what we need, that's okay, too, it's sometimes good to just think about it.
And finally, we should acknowledge and tell your brain that there's no need to set off responses that we would've needed thousands of years ago. We're okay now. The fight or flight response is no longer necessary. We're not in any real danger or under any threat. We should thank our brain for trying to help us, but we should also let it know that it's okay - it can calm down now, because we're safe.