Is it normal that i don't care much about losing friends?

This is normal AND very good I'd say. I too have had a friend, a pretty special female friend of many years after high school who suddenly decided to be distant and rude so I unofficially but definitely ceased contact. The way I see it is, when people who used to be important to you does something bad to break and spit on whatever relationship you had and you personally didn't do anything wrong, that is seriously their loss. There is no reason to stay angry for too long because they are the one who will regret their change of heart, not you. (or me either) One day when you are living it up and enjoying life, they will need a friend like you and they won't have one. Might as well be tough about it and accept it.

Is it like she's dead to you? I get that way about people who I feel have betrayed me; after an obligatory period of hate I relegate them to the dead zone in my heart and mind. It might be a little egotistical of me but it's better than crying or at least I think so.

Trust me i know that feel very well, you feel like you've become cold or something but it's not your fault i think it's due to the several disappointments you experienced in your life, that's actually what makes letting go a piece of cake for you, it's kind of a self protection technique when you're tired of caring for the wrong people, but unfortunately the only injustice this method can cause is the fact that there are people worth fighting for but your previous experiences stop you from seeing it and you treat them just like the rest who hurt you before.
I think the worst position to be in, is not knowing if you should let them go for good, or do a little more effort to save the relationship and i can tell that you were in it since you posted this. I don't know if we are in the same situation but the way I see it is I'd rather give all what I have or nothing at all, i'am just fed up with people giving me more negative vibes than positive and all those mind games, even if they were people I ( care ) cared about, but in fact the only thing that keeps holding me back, is the feeling that i'am hurting them, which i'am 90 % sure?but sometimes you gotta be selfish to save yourself from drowning in depression... People are funny as hell they hurt you and then they get angry and make you the bad one and blame you for walking away instead of just putting aside their ego and apologize to you.

Nothing lasts forever. we all believe that no matter what life throws at every single one of us, we will always have our bestfriends from childhood or elsewhere that makes us believe the bond between the individuals can't & won't ever be broken or fade away ....yet, sadly...as some of us get older we leave behind or get left alone by that one who always said "friends til the end" it's called growing up & maturing.

Can't be that good friends if you don't care about to lose them.

Friends are only friends when it suits them.

And you can always make suits out of friends.