I really need some advice?

I'm 16 (going on 17) an I will be a senior in high school in the fall. The problem is that I am starting to lose all of my motivation. It started during my junior year. I had always been a procrastinator but it would get to the point where I would start my homework around 11-11:30 PM. I was in a couple of AP classes and still finished the year with A's, but I'm afraid that I will fare much worse senior year and in college. I do not think that intelligence is the issue. It's just hard for me to get going. I feel like I have to force myself to do everything from school assignments to chores. I know what needs to be done but I find myself thinking, "what's the point?". Lately I've been really frustrated and depressed and want to talk to my parents about seeing a therapist or something but we're not on the best speaking terms right now. Even when things do blow over I'm afraid of what their reaction would be. They have no idea that I wait till the last minute for everything or how I've been feeling. How can I tell them? Thanks.