Can guardian angels be seen?

One day after me and my friend went shopping, we hung out at my place for a few minutes messing with the piano. We thought that there was someone behind us coming up the stairs but no one was really there. but what I saw was a fading white light and when she left, I went to another room and went on the internet. I looke around to see if there was anything else to do but when I looked right at a closet, I saw a guy about my age. He had a blue appearance with long blue spikish hair at the end, a white tee, with a blue vest like form the 90s, red nikes, a gold ring neclace,some blue jeans, and white gloves going through some of the clothes in there. It appeared for two seconds and automatically disappeared and now everytime I close my eyes, I feel as if it is watching me or coming to me. It seems as if he is always there following me and making sure I'm fine.