Is this a case of acute insomnia?

It sounds more like you just have bad sleep hygiene. You need to maintain a normal sleep schedule. Get up at the same time and go to bed at the same time everyday. If you had true insomnia you would probably not be able to sleep nine hours at a time. More than likely you have your sleep patterns so tered that you get sleep deprived and cannot sleep when it is time. Eventually you will crash hard for a while. And then you will go back to your terrible sleep patterns again. Do things that relax you before bedtime. Take a warm bath, read a book, listen to music. Whatever you like to keep your mind at ease and keep your schedule the same everyday. Eventually you will get back on track. Good luck