For when it's too much, just:
Breathe in, breathe out. It's that simple.
Awareness. Notice your feelings. Awareness arises, half of the work is already done.
Notice how you handle yourself. Imagine (your) caring, calm, warm, kind mother or father.
The first step is to bring you back to the current moment, to the right now, where things are okay, youre just sitting in your room. (of course assuming that your immediate surroundings are okay) Do that a couple of times until your immediate mind is calm. A calm mind thinks differently. The second step is to raise awareness. Sometimes we think something about ourselves or something else but are not really mindful about it, maybe there is another issue going on. Go back to step one if you do feel overwhelmed again. Continue noticing a bit, just noticing, not so much labeling. It's important to let things flow, let go of yourself, and just become a stream of awareness. Right now is not the moment to be thinking, judging or ordering, that will come later. The third step is to reasses your inner voice. With that voice I mean the way we approach things, the way we approach our own feelings and thoughts, sometimes we push them away, sometimes we hate people or ourselves, sometimes we fear things and feel hopeless. Imagine a caring parent, they will take whatever is there, accept it, be warm, kind, and, if necessary, do something about it, because they are strong. You are strong, too. You have that in you, too, and you can become this kind, strong voice. Now you are in a mindset which is balanced, grounded. Now, is there really still something you want? Write it down. Talk about it. Plan. But the way to deal with it is with grounded love, not hate, not fear, not confusion. When you feel safe and warm and strong, your mental space should be clearer and will actually aim for things you actually want. But most of the time, after one, two or three steps, it will already be okay. Not every emotion or problem needs solving.