Actually, what I believe in is very different and might sound strange. Both of those "selves " are mere illusions in our heads. We're not the one who's experiencing everything but the experience itself. We're not the one who's so miserable, angry, or excited, we're that misery, anger, happiness and love itself.
Best advice out of all advices for you would be to learn about mindfulness and eastern Philosophy. I mean, if you want to overcome thyself, be at utter peace, then you'll have to spend hours and hours just observing your mind! ;)
Regarding insta, I had a very active account which I ended up deleting. I still have one with one of my favorite piece of writing on it. Please drop me an email at email@example.com (0 not o) as I don't feel comfortable sharing here!