Alone vs lonely

I just had this random thought all of a sudden. How do people define someone as a loner? We always hear people say things like..

Wah that girl is a loner.
He always so lonely one lah, eat alone..

But what if that person just likes being alone? I like being alone sometimes but I don't ever want to be lonely. At times when I need to clear my mind, I like to go for a run alone, shop alone, take a bus ride alone, go for manicures/pedicures alone.. There is a big difference between being alone and being lonely, but I don't know how to see the difference in real life.

I guess the only thing I could never do is to eat alone at public places, like macs, kopitiam or restaurants. The most I could do alone is to have coffee at Starbucks or to study outside with my earphones. I hope one day I can overcome this barrier! But maybe I will try watching a movie alone first, which is probably not that bad as everyone's eyes are glued to the screen. Oh maybe that's why I hate doing these things alone, I don't want to feel awkward. I think that's the most uncomfortable feeling someone can feel.