I went out with someone back in my country overseas for one evening but it was very nice and one thing I noticed is that we clicked from the beginning but there was only one thing that was keeping us apart is me having to return home back to brooklyn and after a month I spoke with his sister she had told me he passed away and ever since then I feel his spirit around me ,or his image in front of me and I feel very different.but I do know that he loved me.

Love is just about the strongest human emotion we can imagine. It can twist reality and alter memories. Especially knowing you'll never know the outcome between you and someone else. I dealt with this for many years between myself and a long distance friend. Is their spirit with you? No... that is the reality of it. If it's just a strong memory and longing to see this person again, I'd say give it time and life does eventually go on. But if, for whatever reason, you feel something more paranormal might be involved... you don't know what type of baggage this person carried. Non-human spirits hang around people and know them very well, when one passes, it's very common for them to represent themselves as that person. If you start "seeing" this person, be careful... it is not him. It is very possible he loved you... but unfortunately he has passed on and that does not remain.

Yes it is his spirit I can tell the difference ,and sometimes I can feel like a presence around me, even when I'm outside driving his image hits right in front of me ,like he still somehow wants to be round me like we have an unfinished business going on cause we were going to go for long term relationship and stay together. I know I'm not going crazy.please give me some good advice of what I have to do. When I'll be overseas again I'll make sure to go and visit his grave site .thats my first priority.

I didn't say you were going crazy. But it is not him. Ghosts are not dead people. I'm sure it feels like him, looks like him, and it can even sound like him. It's a familiar spirit and it's just acting like him.
My advice to you is to tell it to leave you alone. You are obviously very attached to him still and need to realize that that relationship is simply not going to happen.