What Causes Frequent Spells Of Dizziness For Long Periods?

hello, i am a 34 yr old female who has always been overweight, but in the last year i have lost my job and gained another 15lbs putting me at about 5 2 310lbs. i have pretty severe headaches, ans always have and un the ast yr my pms has gotten to where i am physically yelling out in pain. though all that concerns me i am use to it, however, within the last 3 months i have has 5 dizzy spells that are so bad i have to hold onto the wall to walk and my head spins even idle. last night was the 5th one and it lasted longer than the others. about 45 min. i do not have insurance and am wondering what it might be from. it is extremely disorienting and would appreciate any advice or knowledge! thanks, Amie