It's normal to be overwhelmed and doubt yourself. Every person has their phases of questioning one's self and place in the world. You're not alone in this phase, by the way. It's almost too much pressure on their shoulders to try and be the best and fulfill expectations.
Your worth will never be measured by how you compare to others. As am I, you are a special person with strengths and abilities unique to yourself. It's a very slippery slope when someone seeks validation from external sources.
True self-worth comes from within. It is about recognizing and appreciating your own qualities, your achievements, and your experiences. Your best is good enough. It does not have to please everyone's expectations at all times.
More importantly, you're doing your best and that you are okay with who you are. Take time for self-care. Do things that make you smile and help soothe and recharge you. Keep around people who build you up and support you. Remember that you are worth some love and respect just because you exist. I love you.