scared

hello just wondering if n e 1 could possibly help...iam 25 yr old female and all my problems started about 6 months ago,suddenly just outta the blue i got this constant lightheadedness and an off balance feeling,think i had a few anxiety or panic attacks due to the fact i was feeling something differnt and had never experienced it b4 which was kinda scary.n e way i went to c my gp and he just thought it was an inner ear prob and refferd me to a ent,went to the ent and did some balance tests and it seemd fine.
now my neck feels really sore and i have a pad of fat at the bottom of my neck at the back,still have the constant lightheadedness and when i press the back of my neck it feels kind of lumpy wellnot lumpy but like theres bits of gristle or something like that grinding away, iam at the end of my tether,of course iam thinking of a brain tumour,or should ii be thinking more along the  lines of just anxiety ahhh man its been going on for about 6 months and i swear i think iam, on my way out ...lol can n e 1 out there help or relate ?