Whatc Auses Headaches And Dizziness?

Hi I have recently returned from a 6 week break in Spain. I started with headaches which were more frequent than I usually get. Then I started having dizzy spells over a period of days - everytime I moved, particularly my head, everything would spin and I would lose balance. This was also happening when I lay down to go to bed and when I tossed and turned in the night, like as if I had been drinking heavily (I do not drink alcohol and had not been!). The dizziness appears to have stopped but daily I am getting kind of light headed feelings as if my head is about to spin and I am about to lose balance. Further, I have noticed that I keep saying the wrong word but similar in my sentences....for instance I would say put on your pyjamas (when I meant to say costume) .....this has been happening quite frequently also and I realise after I have said the sentence. I am aged 40 years!