love him or leave him?

so last night i met my real father, he left before i was born and i have only seen him once in my life time other than last night when i was 4. i did fine with seeing him for the most part until he had left. i cried like a little kid. askin why did he leave in the first place. not ready for kids yet? he has another daughter a yr younger than me that can't be it. was i not what he wanted? did he just not care? i don't get it at all.. not having someone who is suppose to be there for your life, someone your suppose to be able to count on, really screws you up. i feel guilty for everything i said about him i dont know why because everything i said was true. n i have his face stuck in my head. everytime i close me eyes he is there.. he gave me a card for graduation with $300 in it. i was like oh my god! awesome.. but i said thank you for the card.. that was it.. i feel bad but at the same point i havent seen him since i was 4. i didnt know what to do. giving him a hug would have been awkward for me. there aint much that can make me cry like a lil kid but i sat there last night n probably cried for at least an hr n a half. i feel like a bad person. for having him show up after 13 years  and actin like nothing had happened.  when he left. i didnt give him a hug i said goodbye and thank you for coming. i feel bad about that too but i couldnt get myself to give him a hug.. i am so confused about all of it.. i really dont know how to feel. but all i feel is guilt and sadness. to some extent i wish i wouldve said more but i didn't know what to say. n even though i've met him twice, i feel like i love him just a little because he is my true father....but i dont want to.. i know thats mean and probably harsh. but i... i honestly dont know.. i really dont.