Hopefully..your professor will understand. But i would think that maybe have your therapist write a note saying something like you are in mists of dealing with something really hard right now and if Professor could help work out some kind of extra work if you miss classes like today.
If you trust him it be best tell the truth..plus it is great practice for family etc. I did have some that understood and others that did not and those made me finally just drop out. It was too hard to work and go through all medical testing. Hope he is understanding...tell him Ghost of Christmas past will hunt him lol!!

I don't know if this will help. A radio station here plays Christmas music 24/7 beginning Thanksgiving and I put it on and it helping me a lot and I sing with some of it.

It certainly lifts my mood and makes me feel really good. Somethings work for some people. If it helps you, see if you have a radio station in you area that does 24/7 Christmas music. [I love the Barking Dogs, the Meowing Cats, The Chipmonks and so many others]

YOU HAVE TO TELL YOURSELF YOUR NOT GIVING IN TO IT TELL YOURSELF EVERYNITE OR DAY YOU TELL PTSD NOT ALLOW DREAMS I KNOW PERSONS WHO SMOKE MJ THEY SAY YOU DONT DREAM I TRUST THIS PRESON I HAVE HUGE TRUST ISSUES . HUGS MINNIE

Thanks for all the suggestions.

I just came out of months of flashbacks. It exhausted me so badly that I could not keep working 40 hours, went down to 17 extremely easy hours. But then I couldn't pay my rent and went through the risk of being homeless.

As bleak as that is I'll tell you the one small thing that helped with the flashbacks. It allowed me to stay out of a psych hospital or worse. I practice meditation. It's weird because I could not possibly meditate during a flashback. It's feels almost like someone saying meditation is good for epileptic seizures. No not at all. But meditation practice helped indirectly. There's this idea that when you respond emotionally too much to trauma memories, it makes it worse. I mean then you over-think it. At first tons of thoughts (and for me self pity) start up along with the flashbacks and anxiety. When I say to myself 'why me' and 'that stupid fuck (step father) he should burn in hell' I just keep thinking and thinking these thoughts then the memories are actually much worse. Meditation practice allowed me to endure the pain without responding to it. I can shut up my thoughts just enough to feel the terror of being a little girl traumatized again and that sucks. But I don't add to the pain with a lot of extraneous thoughts and responses. It allowed me to let go of the feelings of still physically vibrating after the flashback receded. I could let go as soon as possible because I didn't allow myself too much thought and emotions that were only reactions to the pain, not the pain itself. I just felt the pain/memory and let the rest go.

I hope any bit of that made sense. I know it doesn't help with real life problems like school, but it did lessen my pain. I dearly hope the flashbacks stop soon and you can have some peace.