I'm coming from a place that was so filled with self doubt and negativity. I used to hate every single thing I drew. It took me about 5 years to drag myself out of that mentality, it sucks, and it's hard. But it's doable, and the way I broke out was through small steps.
Also I found people that I could trust with what I was going through. This is crucial, there are some things that just cannot be done all alone, we are not islands. It took time, but I let these people help me grow by listening to their advice, and observing how they behaved. Cannot trust everyone, but there are people that are trustworthy, that will help, even indirectly sometimes.