What Do I Do When Being Overwhelmed By Emotions Is Taking Up Time From My Life?

I have always felt emotions on a deep, overwhelming level. Even when maybe I "shouldn't", even if it's over something small. And yet, I don't know how to quickly get over these negative emotions or let them simply roll off my back and go about my day. I have to go be alone and cry or sleep and sometimes that takes hours until I can function again. No amount of reassurance or positive thinking will get me out of that state when my body also physically feel along with my emotions. And it sucks especially when I have had longtime plans for something that I've been preparing for, and then suddenly this little thing completely made me break down and I can't hide my tears or my anger or sadness. It's i credibly inconvenient especially when I end up "fine" later after I have my few hours of crying or sleeping. What can I do about this so it can stop interfering with my life?