What do you when you basically have been so heartbroken you change into a cold person?

I used to be such a caring guy, i was always tough with a mix of being the most shy unshy person you can ever meet haha. I genuinely care about people and there well being but my experiences with women have pretty much just made me numb. I have gotten colder as time has gone on and more hurt at the sametime. The girl i loved does not love me, the girls i like dont like me and whats worse is because of that i have isolated. I saw my friends on friday for the first time in almost two months and then i have isolated again. Just work and home. Family thats it. I have gained weight because of it and just had a temper that i did as a kid. I hate this but i learn the truth is no one gives a **** how you feel women dont care they just want you to care. I work hard i do alot for my family i even stepped up in paying the house bills because my aunt lost her job my siblings love me and there all kids and my aunts and uncles respect me but iam alone. It seems like no matter what i do with women i am not a push over i handle my fights i do what i have to do and to me that defines a man but it seems to never be enough. They expect me to put up a wall with them when its like i just want a girl i can be danny with not the danny everyone else sees but the guy my family knows and loves. This and losing my best friend because i love her and she does not want me has made me so cold and desolate. Iam just not the same guy anymore.. because i learned all people will say is man up yet my entire actions prove how much of a man iam but i just never seem to be enough... what do you do? when your heart seems to not matter to anyone?