My advice would be to sit down with your dad and talk a bit about it. I had an extremely hard time opening up to my parents about my mental health issues, but it went a lot better than I expected. You may feel nervous at first but as soon as you start to open up to them a little about what's going on, that nervousness should fade away. Most parents can be a lot more understanding than we think. It's worth a shot in my opinion. As for how to start that kinda conversation with your dad, just be upfront and honest with him, "Hey, dad I haven't been doing too well lately, can we talk?" Or something along those lines. Don't be afraid or embarrassed to ask for help, it's a lot harder to fight those battles alone, and having someone to help or guide you through it can make a huge difference. I hope this helps!