1. With a thing or a situation, we usually use 'about', as in 'I'm upset about that'. You can also use 'by', but this tends to be more of a passive construction, for example, 'That upset me' = 'I was upset by that.' We don't say upset 'with' something. I'm not sure where you learnt this, but it is wrong. 2. For a person, it depends what you mean. 'I'm upset with her' = I'm feeling hurt/resentful towards her. 'I was upset by her' = She upset me (a passive construction, as above) but 'I'm upset about her' = 'I'm upset about what's happening to her' or 'I'm upset by some news I heard about her.' By the way, we don't normally use 'smth' or 'sb' as abbreviations. These are not standard writing conventions and most native speakers would have no idea what you mean by these combinations of letters. Just use the real words - something or somebody.

It is "to be upset with someone/somebody". I think they're interchangeable, though I am no English teacher so I can't say for certain.

In short all of these prepositions: "about", "by" and "with" can work. There are some slight differences though. Usually you use "about" when you are referring to something, an inanimate object that has made you upset. For example: I'm upset about the weather. He's upset about his exam result. We could use "with" in these instances too, however. For "with" we usually say we are upset with a person, perhaps an animal. We wouldn't usually use "about" in these cases. For example: I'm upset with her. John is upset with his cat. When we use "by" it usually means "because of". We use it to provide a reason why someone is upset. For example: Joanna was upset by David. [Joanna was upset because of David] I'm upset by the bad news. [I'm upset because of the bad news] In fact, I think we use "upset by" very rarely in English. "Upset because of" is perfectly acceptable too and I think it is clearer. We use "upset with" and "upset about" much more often. I hope this helps!

"Upset about" is usually used when you are talking about a situation. For example: I am upset about the car crash. "Upset by" is usually used for situations too. You could say: I am upset by that news. Meaning that news bothers you. "Upset with" is usually used for people. So, you could say: I am upset with Madeline. Meaning you and Madeline are not happy with each other. You would use "upset with" for somebody.