@megmegmeg
I’m sorry your friends seem to take some distance with you right now. This is totally something we all experience from time to time.
The conclusions that come from this situation, the things you say about yourself, the way you see yourself, is understandable because you are hurting. But it doesn’t mean it’s true. I’m truly sorry you’ve been feeling like this. You are so much more than what you’ve been thinking about yourself.
They have much better lives compared to me, they actually seem happy.
Well, I’m sorry to say this but you will always lose in the comparaison game, friend. I get that, we all compare ourselves to others sometimes. There are times when I’m also tempted to do that. But it often lead us to the wrong conclusions, especially when we’re struggling with our self-esteem/confidence. It’s natural to compare ourselves to others, but when we’re suffering it’s just an unhealthy way to validate our feelings and the negative thoughts we can have about ourselves. Like: “I’m not satisfied by my life right now, and if I look at others lives it just shows me how unhappy and worthless I am, how much I’m unable to do anything right”.
Your life, your happiness, is not depending on others happiness. If someone you know accomplish something, it won’t change anything in your own life. If you know them, at least, you would be happy for them. But their situation won’t say anything about you nor what you can expect in your life. We all follow different paths, have unique experiences and ones life can’t be compared to an other one. Also because we all have different representations of what is a fulfilling life. Your standards are not the same as your neighbours. Because your experiences are different and because you are not the same person.
I also want to emphasize the fact that you don’t know if their life is actually better. We never know someone entirely and what’s behind a smile, unless we have a very deep relationship with them. And the fact that you finally said they “seem” happy is very important. Appearances hold a great importance in the way we perceive others. Especially now, with social medias, where people try to show themselves at their best.
So, about this comparision tendency, I can only encourage you to push that back. It doesn’t bring anything healthy nor helpful to you and you certainly don’t need it right now. What matters is you and where you are in your own journey. Always compare yourself to… yourself. Where you were before, where you are now and where you want to be in the future. It’s how you’ll find some direction and guidance for yourself. 
My friends are drifting away and are leaving me behind.
Is there a possibility for you to talk to them about this? In all relationship some adjustments has to be made sometimes, but it goes along with a regular communication. Maybe there are just life circumstances that make them being distant (I suppose the covid situation doesn’t help either), and maybe they’re not even aware of this. So I understand how you feel. And you have the absolute right to feel how you feel. But unless you talk to them to understand what’s going on, then you can’t really know if it’s because they want to be away from you or not. And even if it was the case, it wouldn’t mean you’d be worthless or your existence doesn’t matter. It would only mean that friendships come and go, that people are not always close/distant to each other the same way and that’s okay.
Your worth, who you are, is not defined by this situation. You are not an annoyance and you are not a piece of garbage. You’re a unique person, you have feelings, desires and emotions that no one and nothing can take away from you. So fight against these voices telling you such awful things about yourself, making you think that your existence doesn’t matter. You matter. Your life matters. Being away from your friends is affecting you. Those are circumstances in your life that are meant to change and, hopefully you will all make the best of this situation. But keep in mind that it doesn’t question who you are nor your right to exist. You are loved.