you sound like me, about a month ago, haha!
I'd never been prone to headaches really, except the occasional tension headache that always went away if i took a painkiller or had some water....
then my anxiety started kicking in, and i went off birth control, and POOF... i was having the weirdest, most painful headaches, like i'd never had before.
I actually ended up getting a CT scan done (whole different story :p) and it came back totally clear. The doctors all did various neurological tests (reflexes, etc) and i passed with flying colours. They assured me that if i had a brain tumour, i would have failed these tests and would be much, much sicker than just a headache. (Plus the CT scan came back 100% clear which ruled out a tumour in itself
Once i stopped stressing about the headaches, and let my hormones regulate themselves a bit, they've stopped becoming an issue.
Also, if you get ANY relief from an ibuprofen, i doubt it's a tumour as well! from what i've been told about BTs (and i've done a lot of research lately....) the pain gets increasingly worse and worse, is accompanied by other symptoms, and cannot be relieved.
Just rest, and try not to let the anxiety get your mind racing. I know that's hard... but I can assure you these headaches happen to a lot of us!