I have had (in my opinion) an extremely hard life.I will not go into details but I have never met anyone who has been through as much as me in their life.I try not to pity myself but it is hard.I get away with everything because people just say "it isn't her fault she has had a very hard life". I think my life has toughened me and made me cold and unfeeling and I do use my hard life as an excuse for everything bad that I do.
Try doing something nice, it will up your self esteem no end, even if its a small thing.
You just posted about the drugs, drugs will damage your self esteem.