There's not much context in your situation. So, I have to make an assumption that you are not able to cope with current friends due to some imbalance in your own mental health. If that's the case, getting new friends will not make the situation better, at least not in the long term. After a few years, you might find yourself in the same situation as now. It's like that old saying: "If someone finds the whole world dirty, then perhaps it's his own glasses that are dirty". So, work towards bringing a balance towards your mental health.
Also, it's just impossible to find a perfect friend with whom you are always going to be happy. Make yourself the best friend you desparately need and you will feel fulfilled forever. You will never feel lonely again and having friends will only bring you more joy.
If you are trying to reduce overthinking, an easy fix would be to try meditation, yoga, exercise, etc. Whenever you find yourself overthinking, stop for a moment. Slow down. Take a few deep breaths. Sense your surroundings. See things. Hear sounds. Engage all your senses in the immediate environment. You will find yourself more calmer.
If that does not work, then consult professionals who will help you work things out. I would highly recommend consulting professionals over taking advice from strangers like me.
I wish you the best and hope things work out for you.