Is it normal to care as much as i do about someone i miss ?

About a year ago I got involved with a group of people online who were bad associations in that they were discouraging, and lead me to unreasonable extremes to try to help them.

I am wiser now, and know that sometimes people need professional help, and also that often people can help themselves to feel better. There is however one person I genuinely cared about a lot, and I knew she was sincere. I viewed her only as a friend, so my caring about her is purely that of a friend's concern.

This person I tried to help for longer than the others, but eventually her problems weighed on me so heavily that I realized I had to stop associating with her for the sake of my mental well-being. So I did, after leaving her a message that said "Okay, now that you have things together I know I'm no longer needed."

The truth was though, I know she wasn't 'together', because a few weeks prior she had sent me a horrible picture of her arm which, well, I don't feel comfortable saying, but she needed help, trust me. She would talk about doing things to herself that are bad, and now that I've left I don't know whether she's done them or not.

She was such a sweet person to, but I'm worried I did something that made her think badly about me. In the chat room where we spoke I looked at inappropriate things, and even though I put a lock on the room during that time I think she may have known, and from then on she didn't want to go into my chat room. The fault is my own for this, and I shouldn't have catered to my selfish desires, but should have abstained from such an unclean habit.

To this day, I feel bad that I ruined my reputation, and just wish I could tell her I'm sorry, that I'm really not a bad person, and that I cared about her so, so much, and still do.

That's the thing though, I don't know if it's normal to care about someone this much, to the point where hearing their name is painful, and hearing anything about what they were doing to themselves or wanted to is also painful. There's a certain character from a TV show I like just because it reminds me of the person I tried to help, and I don't know if this is normal.

So I'm wondering, is it normal to feel sadness over someone even though it's only been 6 months ?

Please comment below, and be nice. :)