Is the caffeine new? Sometimes too much caffeine gives me bad headaches...I'm just brainstorming here but usually the answer lies in the diet. Dammit! lol
I'm with Cali here... Diet changed right before the headaches, right?
I was thinking in the opposite direction, though. If you cut back on caffeine too abruptly (or nicotine or alcohol) you can get nasty headaches.
Same with if you're dehydrated (which might be relatively so if you're taking more supplements).
Also, I can't remember if you mentioned it or not but are you taking Clen or anything other than the Anavar?
Stevia sometimes gives me headaches as do some of the other artificial sweeteners. Sorry to go all Matlock on you but sometimes the only way to sleuth it out is trial and error.
Finally, Radar brings up an interesting point... Definitely get your blood pressure checked. You can do this for free at many pharmacies and it takes 60 seconds. Kinda silly not to.
Other thoughts... I (and a lot of women) get horrible migraines. I went to neurologists, had MRIs and CT scans and still about every other month would wind up with an ER visit for a headache and vomiting that would turn out to be another migraine (hot, I know).
In the end, it turns out that what triggers my migraines is muscle spasms in the nape of my neck and the small muscles at the base of my skull. I'm especially vulnerable to straining these when I'm starting a new program and have to stay cognizant of not tensing my neck (lol... This can even happen, um, in bed... Sorry Mom). This is easy to test for by feeling the back of your neck for "knots"... Tension even in the traps and shoulders can generate this too.
Just thoughts... Obviously if you haven't figured it out soon it might make sense to see a doc.
Hope you feel better soon!
xo