If I am gaining 20 points for winning and losing 20 points for being defeated

According to your mmr, you are where you should be. Here is where you should start focussing on improving yourself and playing some normals before hopping into ranked to make sure your internet and frame of mind are at their best.

i don't think it's that easily summed up.

When you're beat, was it just a fluke and the enemy got lucky?
Or will you learn and adapt to better yourself against players who outskill you?

When I feel I can't climb anymore, I try to keep these questions in mind. One is the correct way of thinking, even though I want to believe the other.