How to deal with Emotional Dysregulation?

I have been fighting with myself for a long time to actually "feel" my emotions. My brain always looks for patterns and expects the worst out of every situation. Its a terrible fight that I just cant seem to get control of and its driving me insane and hurting my relationship. For a very long time I've cast my feelings and emotions to the side and really just focused on pleasing those around whom i care about. It didn't seem bad at first, but there's only so much I can take until I break. Its like putting a cup underneath a dripping faucet, eventually its going to overflow. I battled this my whole life, turning to drugs and alcohol to escape the madness of it, almost like hitting a reset switch, but each time i hit that switch the reset period got shorter and shorter. I got into a pretty bad depression with it, and almost decided to end things. When I woke up the next morning I decided that enough is enough and that I had to make some solid changes to get better. I started to confront my feelings head on, but I was not prepared for it. Every negative feeling i get is like a physical pain in my stomach and my mind connects the dots to the worst possible outcomes and latches on to it for dear life. I feel like I am experiencing things for the first time (which i guess I kind of am) and I don't know how to process it correctly, almost like a child learning how to cope. I've done a lot of reading online for self help therapies and such, but nothing really seems to stick. I feel like I need to train my brain not to immediately react negatively and how to unlatch from those negative thought patterns but its so hard to do. I think its because i've been doing this my whole life, but its difficult to try to break this cycle. It almost feels like my brain has developed this as a coping mechanism and is giving me every reason to go back to "not feeling". I guess i just want to see if anyone has the same problem as me and what have you done that's helped?