beggars & conscious

i was at a photo shop to get a picture size passport. a girl covered and speaking in good english took my picture and i left the shop so i return later to get them. as i was leaving the shop, this guy came in. he was obviously begging while talking in arabic. i couldn't understand, but he then followed me and start o speak in english! that he has 4 kids and he's sick and jobless. i chose to walk away and don't pay attention. i can never tell which of them tells the truth? i chose to walk and now it is eating me up. i don't know how could i help him or if i could help him at all, but the fact that i ignored him has not left me alone ever since that encounter. there are two scenarios to this. either he was telling the truth or lying. in any case, i wish i could have done something or at least listened to him! but what should really be done in such situation. if you give money, it's not reasonable, if you chose to walk away, then it's again not fair.
i still can't get rid of the image of that african boy who was staring at me few months back, when i finished shopping for fruits and grocery. i could easily walk up to him and give a bag of oranges or apples, but i chose not to. why? i'm ashamed to say that i was thinking what others would think.