You don't say how old you are. But you might be developing an anxiety problem. There's a difference between stress, which is from something really happening that you put too much pressure on yourself about, and anxiety, which is usually not really traced to anything new going on. Suddenly things that never bothered you do. Sometimes you can trace this back to something that happened about when the problem started and often you can't. Either way, if it becomes such that you can't fix it yourself and it's becoming chronic, seeing a psychologist who specializes in anxiety treatment is a good place to start.
Okay, had to just check my son's computer to make sure this wasn't him! Yes!! He is the same. It's almost like the adrenaline drive after a stressful period like exams and then sort of an inability to relax after. Now, my son does have anxiety. He worries a lot. He puts a lot of pressure on himself. He's a perfectionist and has low self esteem and maintaining his perfect grades is all tied up into things it shouldn't be (we are working on that), It's really hard on him. And then he tells me that things like the holidays, he feels internal expectations that they are supposed to be wonderful and if they aren't, that is stressful. And you know, not being wonderful can mean his brother bugs him (daily) or I tell him he has to unload the dishwasher or a friend didn't text him . . . so, everyday things. Do you also have an idea in your head of how everything is supposed to be and get upset when it doesn't go that way or nervous?
My son also has issues big time with sleep. Two things that have helped. Years ago we got him a very heavy weighted blanket. They are all the rage now sold everywhere but the key is that most are too light. You need the heaviest you can find. That is what our occupational therapist told us. But it has been great for him. Something else introduced to him by his therapist are meditation apps. Calm or Headspace are two good ones. My son when he relaxes his body, immediately will fall asleep. Those apps are easy to use. Headspace is free.
The way I feel about it is that addressing mental health is never a bad thing. And a psychologist or good therapist can make great progress in helping someone find coping strategies or even just feeling like what is going on mentally for them isn't abnormal. By that I mean, everyone has stress from time to time and lots of people have anxiety. It's good to not feel like you are the only one. After having recently gone through securing a psychologist/therapist for my son, I think one of the most important things is to pick someone you feel like you can have some rapport with.
How are you doing a couple of days later? Has your stress/ nervousness settled a bit?