Yes, it will get better. Along the way you will likely fall back off that cliff many, many times - it is a part of the journey. There will probably be times where you feel like you are right back where you started, and all your old coping mechanisms come back into play because right at that moment they are the only thing you know that helps.
But you are learning and growing and changing all the time, even in those times when you feel like you have not changed or learned or grown at all.
All of those tiny steps forwards take you to a place you have never been before, even when they are immediately followed by yet another fall back into those dark places. Every time you emerge out of those dark places you are able to inch forward yet another step, moving slowly but surely ever closer to the place you eventually want to be.
The journey may take you to the highest of peaks and the lowest of valleys and, at at times, around in circles, but the most important thing about the journey is this: You are on it.

Keep going. You will get there.