I'm scared for my relationship?

i am in a confusing situation. i had a pionate relationship with a guy for 2 years where we were so in love but halfway through the relationship things like depression, self doubt, and insecurities hit me, and my behaviour towards him got really bad.. i started getting cranky all the time and not being so sweet to him.. he was a very peaceful guy so he couldn't take the daily bickering and eventually left me. which needless to say was terrible for my low self-esteem and depression at the time. i felt worthless and went into depression for a few months. then i snapped out of it, gained confidence, stayed happily single for a few months, then met my CURRENT boyfriend. when i met him i really liked him but warned him not to be with me because i am emotionally unstable and not ready for a relationship. he said he wanted to be with my anyway so i said ok. we've been together for 5 months now (i'm 22 and he's 25) and my insecurities are back... i feel like he'll leave me, i feel i emotionally drain him as i constantly need reurance from him that he likes me (we haven't declared love yet) and that he thinks im pretty etc etc etc... again we bicker daily and he gets over it fast but i'm afraid the same thing will happen... he will leave me too the same way my ex will... this guy treats me sooo well it's amazing.. i feel i don't deserve such an amazing man.. i complain about everything and expect so much from him, which he is so willing to give but still i am not convinced that his feelings are real.. what is wrong with me.. i can't help feeling so insecure.. but i did warn him.. i told him we made a mistake to get together but he says he wishes i wudnt say such things cuz i mean so much to him.. i don't want to lose him or break up and neither does he but i feel i am making him miserable (but he never tells me that, he says i make him happy, when i am sweet to him)