You are making choices. The fact that will isn't "free" doesn't mean that will doesn't exist. I think you're overusing reductionism here. You are making choices, you are just making them according to logical processes.

When you make a choice, that whole process may exist as a series of predetermined chemical mechanics in your brain. But you still control the choice you make.

When you say that you can't not do what you are doing, you assume that you yourself are separate from your choice. But you aren't. You are a result of causal mechanics as much as anything else. To say you "can't choose not to choose what you choose" is like asking whether God can create something so heavy even he can't lift it. There is no "you" to not do what you're doing. You are part of your choices, your choices reflect you and you reflect them.

The assumption of some outside "agent" who is limited by determinism isn't consistent with the idea of determinism.

To put it another way, you don't have the ability to float into the air. Does that mean your body limits you? In a certain sense I suppose it does - but there would be no "you" to float into the air without your body. Regardless, being depressed because you can't magically "go against" gravity seems silly to me. I believe determinism and a desire to "go against" determinism are similar.

What is it in particular that makes you feel depressed?