Strange Lasting mild headaches, feel like brain freezes, and sinus pressure (4 months)

I almost never get headaches normally. About 4 months ago I started feeling foggy in my head and having mild headaches in the front of my head above my eyes. This feeling has persisted off and on ever since, usually mild symptoms. I don't have a stuffy nose at all, but I can feel sinus pressure above my eyes and in my temples. Sometimes my head feels almost like I'm constantly having a mild brain freeze. Rarely I'll feel a shooting pain somewhere else in my head that only lasts a moment. The first month of this I went to a doctor and they gave me azithromycin, which maybe helped slightly, but I'm not really sure. It definitely did not cure it. Last month it felt a lot better by itself, but not fully gone. Now it's feeling a lot worse, almost back to how it felt in the first month. I've never felt anything like this before and now it's a constant feeling ranging from very mild to medium intensity for the past 4 months. What is this?