Do you drink caffeine? If so, lay off that or don’t have it after say 2 PM. I see you are in France so I’m not sure if it’s legal but some people say marijuana helps them sleep and without the grogginess of Benadryl or some other sleeping meds.
For fear of this thread being locked (it is a family forum, after all), I can attest to this. I wasn't going to be the one to say is, however I found long ago that THC helps slow my brain/thoughts enough to be able to sleep. I have the problem of just not being able to close my eyes without every little niggle of the day replaying in my head, which can make sleep almost impossible.
I'm a regular "weed" smoker, however I use it to balance my mood swings and generally short-tempered personality. I don't mean this to come across as self medicating, as I don't have multiple personality disorder or depression or any true psychological disorder, I just recognized years ago that I have a short fuse which has caused me issues during the course of daily life. THC provides just the right amount of.... treatment? to more or less allow me to take that extra 2 breaths and re-evaluate situations I'd normally over-react to.
For sleep, smoking actually is a detriment in my experience. It causes me to analyze more, think more, and therefore leaves me unable to detach from the day and fall asleep. However, edible forms of THC provide just the right balance of relaxation and disconnect to be able to drift gently to sleep, get 6-7 hours solid, and wake up without the slightest hint of side effects.
My favorite is my medicated hot sauce. Spice up a simple dish like a baked potato, a bowl of mac n cheese, heck even a few drops on a crunchy veggie like carrots or celery works wonders. It really doesn't take much, and takes a while to kick in, giving you ample time to naturally wind down before the effects kick in.