Welcome Little Miss Headache!
I feel for you. Nothing is worse than having a headache everyday. I think you'll find a lot of us here have experienced or are experiencing similar chronic headaches.
Are you seeing a neurologist? I find my neurologist extremely helpful in narrowing things down.
I have followed a similar pattern and I'm pretty sure that I'm caught up in a cycle of rebound headaches. Some of the medications you mentioned are known to trigger migraines or cause rebound headaches. The severity of your headaches definitely sound like migraines - though I don't have any medical training just lots of experience. I have found that my rebound headaches can cause migraines.
Triptans (i.e. Zomig and Imitrex) are known to cause rebound headaches. Some anti-depressants (I know for sure Celexa but not sure about Paxil) are known to trigger headaches. Birth control can cause migraines. I'm not sure about the others. If I'm not sure I often research them on the web and am able to find out if they're know to or not. Or the medication documentation will also tell you if it's a risk.
Another thing I have tried and found somewhat successful is identifying triggers, especially foods. Try avoiding things like coffee, chocolate, aged cheeses, red wine, MSG, nitrites, nitrates and anything with preservatives in it. There are many good books out there that explain them.
There are a few thoughts that might help or you may have tried them already. It sounds to me like you need some expert medical advice, like a neurologist or pain specialist.
Coquitlam55 (aka Nicky)
"The world is full of suffering, it is also full of overcoming it." --Helen Keller
I try and remember this each day I have a headache that I'm not sure I can overcome.