It doesn't matter if you feel like you can diagnose yourself or not. If you're feeling weird and you don't like it, it's a good idea to see a therapist. An ounce of prevention is worth a pound of cure.

Even if it's just a dip in motivation or some low-level anxiety or something, it's worth it to work on it with a professional. Everyone has things they can work on.

One viewpoint is that "depression" often presents with only a small set of symptoms. For instance, in middle-aged men it frequently presents as only physical symptoms. Also it is very possible to have some of those symptoms and not realize it or have your doc realize it.

Just keep it in mind. Maybe you need a vacation.