Doctors are worried I may have brain cancer.

Well first of all I live in Canada and yes it's free to get everything you need done.but with that said I beleave you get what you pay for.I have been over the past two months having headaches every day and they will not go away.doesn't matter if I take anything for it.I also have lost my short term memory and a good chunk of my long term.I also am having trouble talking at times were my speech will get very slurred.I am blacking out often.for example if I'm driving from point A to point B I can't remember anything about the drive there or what happened to get me to point B.In the past week I have started to get dizzie.I can only compare it to being very drunk amd getting the spins.Also my eye sight has been getting blured.I have had a ct scan and I went in today amd it showed nothing up.my doctor then said that ct scans don't mean that there's nothing there amd that he can't get me the real test I need quickly due to the way are medical system is here.and that he thinks I should go to the er one night complaining about everything amd hope they do all my tests right there.

My question to everyone is do you think I could have brain cancer or something else wrong in my brain?and how worried should I be?