where are my holes?

[sds4255]

ok i have been playing 1/2 limit hold em for about three months and I have lost about 50 bucks overall. Here is my problem, it seems I have really good sessions where for about 3 hours I will win around 40 bucks but when the cards dont come my way i get blinded down 20-30 bucks at a time so I ll have a good session then two bad ones? What are my problems I play good cards, and lean towards being a tight player becuase playing bad cards doesnt intrest me? Any suggestions???