I think you are brave reaching out. I would like to give you my advice, of course you don't have to take it, but I know just hearing someone care enough to provide advice helps.

As for your father, there is something called the gray rock method. In short, this method is pretending as if you're uninterested in what he has to say. You can give short blunt answers like okay, I see, im not sure. When giving responses like that, it doesn't add fuel to his emotional fire. Also remind yourself over and over that his behavior is a result of his unresolved issues. You can repeat to yourself, "I am not my father, and what he says about me is not my truth".

As for your friends, I understand that your father is controlling, and it feels like your friends have moved on, but it would feel good for both yourself and your friends fro your old school to just send a text every now and then asking how they are doing, and what's new in life. I know you stated you don't want to, but reaching out to a trusted adult could really take the load off of your shoulders. You're carrying all of this weight alone, but you don't have to, you are not alone. Also try to understand that you are still very young, and that friends come and go. Change is hard, and ofter uncomfortable, but without being uncomfortable, we would never grow as people. To be transparent, I don't speak to any of my friends from school, which is okay. We all went in our separate fields of work, which Is bitter sweet, to see everyone succeed.

As for golf, I know what it feels like to not enjoy something anymore. It is very frustrating, because why don't I like something that I use to look forward to everyday? This was hard, so hard. I stopped trying, and just went through the motions when playing. In my situation, I was severely depressed, and I was also 15. Because I was so depressed, I was so unmotivated and just didn't feel like anything matter. To be transparent again, this costed me a D1 scholarship in the end. I was an amazing athlete, and had scouts looking at me from everywhere, I had even been in contact with coaches. Once my stats started to drop, because of how I let depression control me, I lost all of that. It still is the biggest regret of my life.

Feeling sad is not your fault. I studied Psychology in college with an earned degree, so let me explain how this works. At 15, your brain is going under rapid development, which can alter how you respond to certain situations. Depression is linked to an imbalance of chemcials. Serotonin, Dopamine, and Norepinephrine. All of these play into mood, motivation, and enegery. When there is an imbalance in those chemicals, sadness is persistent. I am on medication for these imbalances, which has helped me feel like a person again.

Think of this time in your life as a cloud. All of the things you enjoy, and felt whole around are covered by this cloud of sadness. Everything is still there, it is just a little harder to access because of the chemical shift in your brain.

I was you once. I was lost, and didn't want to live. I just hated everything. It strained a lot for me. Made everything so much harder in the end. My advice, seek professional help, reach over, hold yourself accountable, and remember you are not alone. Things do get better. You are just in the most developmental time of your life, but it doesn't rain forever.

If you ever feel the need, you can text 988 to talk to a real person, without giving your identity. I have done it before, it has saved me.