Problems with betting/gambling

Hey guys i'm new to the forums and i was recommended that this place is the place provides a lot of information. first off i just wanna talk about my first problem....

when i come to a casino or play online poker, i always start on a low bankroll ($5 to penny tables, $25 max buy-in for .5/1.00 nl beginners table). but my problem is when i bet, someone raises me, and i know i have a decent hand to play with, i tend to fold and get bluffed at almot 70% of the time. i guess it's because i'm gullible, but i need advice on how to play effectively and efficiently. thanks twoplustwo guys [img]/images/graemlins/ooo.gif[/img]