tired and dizzy

hi im on this site right now because i need to find answers to my condition. im 22 years old and i have some depressions mood in my 20s. i worked full time at night and go to college in the day . i worked 32 hours per week but i sleep at least 4 to 5 hs at my work because i have the possibility to . BUT every day ,feel so tired and sometimes dizzy so much that i cant concentrate or do anything. im so tired most day , i sleep in class , miss appointement and start losing stuffs around me like my wallet or my phones , please im really confused about my life right now , plase help....