What Causes Disorientation And Nausea Along With Headaches?

ok, for about 4 to 6 days a few times a year i get these feeling of disorintation, nausea (no emesis), heart racing (sometimes) nervous stomach, confusion (have to keep telling myself where I am and that I am ok), headaches (sometimes) feeling of uneasiness, lump in my throat (sometimes) dry mouth (sometimes) , sometimes it happens either beform ar directily after my period, I am 53, this has been going on for at least 40 years. when i was 11 i was diagonised with siezure disorder and i have been taking 300mg od dilantin daily. what do you think