Maria, I am also on Topamax. It's not doing a lot to help my migraines and I probably won't be on it much longer (but I love it for weight loss reasons). I've tried lots of different meds and none of them help. The only thing that seems to be helping is a progesterone cream, applied nightly, since the hormonal changes of perimenopause seems to trigger them in a lot of women my age (I'm 45). I just started that treatment, so too early to know for sure, but it seems that instead of headaches 3-4x/week I'm only getting them that often the one week a month I'm not using the cream. Thought I would mention that to you in case it's something you haven't tried.
My migraines were so bad that I was taking daily meds and getting rebound headaches. I had to take oral steroids to try and break the cycle of the meds. Not fun.

Even when I didn't have a headache, my head had a dull ache all the time. The last month or two is the first time in a few years that I haven't felt horrible. I still watch everything that I eat and drink (alcohol, cheese, etc).
OP, I hope you find your answer and it's something simple like a sinus infection.