I've thought about this a lot and what makes me keep going is my end goal.
For something like martial arts, you can't just be focused on some distant "finish line." It's okay to have goals, both short term and long, but you need to be engaged in and appreciate the daily process or you'll never stick with it long enough to get anywhere. "Failure" is part of that daily process.
I want to be somebody worth remembering
Strive to be remembered for being a good person who makes life better for those around you. Even if you become a really exceptional martial artist, most people in your life won't really care about it. It'll just be a bit of trivia they know about you - your favorite hobby.
and in general good at something
That's an understandable desire. As I mentioned in a recent post, the drive for mastery - to feel that you are really good at something - is pretty fundamental to a lot of us. That said, the only way to get really good at something is to really suck at if for a long time. The biggest difference between a beginner and an expert is that the expert has made way, way more mistakes than the beginner and has "failed" more times than the beginner has even "tried."
It's just the more and more the I train I feel worse about the situation, all that happens is I see more and more how far away and out of reach the goal is.
This is a natural part of the learning process for just about anything. Your understanding and your standards increase faster than your ability, so you become increasingly aware of the distance between what you can do and what you want to be able to do. It can lead to the illusion
that you are stagnating or regressing even though you are actually making progress. Just remember that it is an illusion. Many times this sort of feeling precedes a significant breakthrough in your advancement.
I'm not going to offer an opinion on whether you should continue in the martial arts. That comes down to you and what you get out of your training. I will say that if you want to achieve significant expertise in
any field - watercolor painting, robotics, home remodeling, guitar playing, juggling, whatever - then you'll have to go through this same process - struggling, "failing", feeling like you aren't making progress, feeling like you are worse than the people around you, and so on. If you don't, there is a significant possibility that you are deluding yourself regarding your level of ability.