I am 25 and have suffered a similar scenario.
First off, you are 22 years old. Most people feel frustrated and lost in their early 20's, so you are not alone there. Have faith that you will soon find a path that will suit your own personal needs; financially and mentally. There are careers out there that are fun, easy, and make good money while you grow. Think of something that you could do endlessly, without pay, and try to find something that involves that. Pay attention to what you are attracted to. And DON'T EVER give up. If the path you choose is blocked with sh*t, another path WILL give you a shovel.
When it comes to other people, you need to have what I call a 'healthy selfishness.' Yes, you would give the shirt off your back for anyone, but you don't need to. There are people in the world that ARE worth a sh*t out there. Look for people who are motivated and focused on improving their lives and find something you like in them. If you surround yourself with people who think positively, it WILL rub off. Another thing that I like to say is "if you look hard enough, you can find a little good in anyone." A good exercise is to seek out good qualities in every person you meet and try to apply them to yourself. i.e. Danny shakes everyone's hand when he walks into a room. If you shake everyone's hand when you walk into a room of people you don't know, you instantly have a level of respect (no matter WHO they think they are.)It is not changing who you are (so to speak). It is knowing that you are improving yourself a little everyday that will keep you rockin'.
In reference to your ADHD/anxiety:
I am not a medical doctor, nor have a studied these "diseases". But, because I suffer from them myself, I have found ways to cope with them. First off, forms of self medication such as drugs and alcohol should be kept moderate to none for a million reasons. I am so much better with a sober mind. Plus, groups of people who are associated with drugs are normally non-motivated, full of drama, and are normally in trouble legally and/or financially. Second, Alcohol and ADHD medications (if you are taking them) do NOT mix. It is terrible for your heart. I take aderal to help me focus. I have found that even if I am not drinking and taking it at the same time, it has cause increased stress and anxiety (much similar to what you are explaining above). Also, if you are taking medications, make sure your dosage is not too high.
In any case, I recommend that you talk to a therapist or a counselor about how you are feeling. Like you, I have been through a lot of crap in my lifetime. But, it was not until I learned how to love myself that I was able to let all that crap go and move forward. Two therapy sessions had me letting go of a 20 years of crap. I think that everyone can benefit from the words of someone who knows what to say.
When I was 22, I felt just the same way that you do. I have kicked the anxiety, but I still (and forevermore) will have ADHD. Last year I made 50k doing something that I love to do. Just have faith.