Yes.
I think of mindfulness though as more looking for something to be grateful for in the moment, vs where my thoughts lead me.
As far as emotional regulation goes, it's good to voice how you really feel, just to the air, even if you're not quite sure what. And/or to continue with why. Somewhat mindfulness but to sort of take a step back and look at the situation from a distance. Also to recognize H.A.L.T- 2 or more of (are we) hungry/ angry/ lonely/ tired it will be very hard to regulate the same way as without. Of course exercise or ways to let off grief or steam, hopefully non-harmful ones: walking, a hobby, going somewhere safe and private if possible, such as in nature; animals, music, sleep, something you like.
For me, and I can't say it takes care of the overwhelm always, or perhaps the broken-heartedness remains, but when it's just difficult (even small things or everything) or painful, I try to put one foot in front of the other and offer it up for the people I care about. Especially when I have no choice to function or to put on a face.
I try to to think, "how important is this?", or also acknowledge why the moment is so painful. Also to accept many people seem to not really get it, so to choose where my heart feels safe or not. I suppose I have bigger things and a bigger history that effects me now than some people do, so for navigating life I have to do what I need to do for myself whether people get it or not.
Welcome to you!

Fortunately circumstances make it feel like they will always all end the same, but we really don't know that. I hope also when you are bereft of hope something or someone can help give you some. And that you will be able to keep challenging your inner critic/ your dad's (or any other's negative) voice by the mindfulness when you feel or hear it to realize that was cruel, I am sure uncalled for, but also his problem and now it doesn't help to allow that to keep feeling like it was true or accurate, even if it's very foreign to challenge it or believe otherwise. Baby steps. You deserve peace and worth.