Can I learn some self-defense on my own? I mean I don't really want to have professional martial art skill, but I want to be able to defend myself if facing someone attacking me. Can I learn that by my own? If so, is there any suggested resources to do so?
You can learn self defence on your own. However, you cannot learn to fight alone because of lots of reasons explained elsewhere.
Self defence is just stacking the deck in your favour. Martial arts are a useful addition, if only because they give you self confidence thus making you less of a target. There are many steps you can take to protect yourself that have nothing whatsoever to do with martial arts. Many (if not all) of these, you can learn by reading, although some will require some physical skill -- for example, gardening to plant roses below your windows.
A lot, if not all, of self defence features not getting in situations where you have to fight to keep safe. The latter should be avoided at all costs, as the risks far outweigh the benefits. I would rather lose my wallet (which contains nothing I cannot replace within 24 hours) than be stabbed. Better yet, not be there when someone pulls a knife…
No nonsense self defense is a good place to start and contains very useful information.