Just know that you don't have to put up with others treating you poorly or taking advantage of your kindness. It may not seem like it right now, but with both platonic and romantic relationships, there are people out there who will treat you right. There's never just one option for a friend, partner, or acquaintance. So, if there are people in your life consistently making you experience negative emotions/thoughts, distance yourself from them and move on to better things.
It's easy to become discouraged seeing other people who can create art, play sports, make music, cook, and do a variety of other activities so well. You may feel as if you don't measure up or have a special talent like they do. However, you're brimming with certain talent and limitless potential. You just need to find the talents and skills that are right for you.
Know that your feelings are completely valid, always. Your emotions are your own, and they're important because they're important to you. You have the right to feel whatever emotions you feel at any given time. And you're not wrong for feeling a certain way.
Always do the right thing. Do what you know is right, deep in your heart. Other people may look down on you for doing so, they may shun you, they might berate you. It may be difficult, but in the end, you'll have peace of mind in knowing that you did the right thing. You'll also have a clear conscience and feel rewarded from doing what your heart knows is right. So always do what you believe is truly right, even when others won't.
Don't compare other people's productivity and progress to your own. Both are going to be different for different people. Don't feel bad because you're seemingly not accomplishing as much as others. We all have to navigate life in our way, at our own pace. Do that in a way that's comfortable and right for you.