I normally went just to trim the ends, but they cut my hair really short. I can say that I no longer trust the hairdresser. My workplace is a very formal environment, and I feel terrible right now. How do you think I can manage until it grows back? Or should I wear a wig or something, as suggested? I’m feeling very helpless right now.
This happened to me once when I was in university; while trying to straighten my hair, the hairdresser actually burnt the ends. I think if there’s a way to salvage it, ask a friend or consult another hairdresser, they might suggest a more natural style.
It has happened to me too, and it’s even more uncomfortable because it gets noticed in a formal environment. But, for example, I had styled it with a graceful clip, slightly tousled, maybe you could try something like that as well.
Well, if you say “short” now, have you clearly shown how much shorter it will be? Hairdressers can sometimes misunderstand, so I always show the length line beforehand—that way I never experienced that mistake 
You don’t have to resort immediately to a big solution like a wig for short hair. Stylish updos or braid styles are recommended, especially in formal settings. If it’s not manageable at all, you might consider consulting a specialist and even think about more permanent solutions like hair transplantation.
Update: Even my boyfriend noticed, and he usually doesn’t say much about my hair. I’m feeling pretty bad. I’m trying clips and stuff, but my head looks huge. I should probably look for another alternative.
The issue of consent is very important, so they have no right to say “we kept it short.” Their exceeding the length you mentioned puts you in a difficult position, especially since it will affect the work environment. You might consider filing a complaint if necessary.
I suggest you go for direct hair accessories. Headbands, wide hairbands, or elegant clips. With these, you can both make your hair look neat and create an impression as if you’ve specifically chosen this style 
I swear I experienced the same thing, when someone at work came up and said, ‘What happened to your hair?’ my face turned red. I immediately got a hair treatment oil and massaged my scalp every day to make it grow quickly. I also saved it with a braid style.
Let me extend the discussion, but I need to add something: Isn’t it a bit excessive to feel this helpless just because of hair? When a person becomes so dependent on their appearance, it leads to other confidence issues in life as well. It’s something to think about 