We don't realize how much of our emotions and selves we strictly control throughout our days just to seem normal and get by. So in moments of relaxation, these things HAVE to come out.
I agree with Reclusive, and I also experience this. I actually want to cry when I am going to sleep and when I wake up, so I often both avoid going to sleep and then in the morning waking up--very frustrating. At night, I feel suddenly flooded by everything I didn't let myself think about, and in the morning, I am flooded by all of the things I will have to think about that day and all of the things I shouldn't think about and the glimpses of nightmares that I had the previous night. Yeesh. This makes my fiance pretty mad, so I've been working on distracting my mind and having healthy bedtime rituals.
Here is a suggestion for a ritual I used to follow to help with insomnia/being overwhelmed before I went to bed/nightmares/difficulty staying asleep (waking up screaming or crying). I apologize that it is so long, but I have gone back to this ritual regularly and it has always helped me.
First, listen to your sleep cycle. I get sleepy at about 11:20PM every night, have done this for years. It's something that I had to pay close attention to before I could isolate the time, though, as anxiety surrounding sleep usually makes me ignore the subtle changes in my body that signal my natural drowsiness. After I isolated this time, I would prepare to go to sleep at about 9 or 9:30 by not engaging in anything that required focus or emotional engagement. No games, no heavy reading, no movie or shows for an audience above the age of 10. I usually watched children shows or movies for a little while to destress, had some soothing herbal tea with a dash of honey, no sweets otherwise. I covered my bedroom in a lavender scent, particularly my pillow. I thin lavender and mint are both supposed to induce relaxation/sleepiness? Not sure about mint. I dimmed the lights about 40 minutes before I had to go to sleep and would not stimulate myself with anything 2D--no computer or TV. Instead, I did things like knit or draw, something meditative and relaxing. Putting puzzles together could also be fun unless it causes you some sort of stress. Grooming tends to soothe me, so I would often spend time doing personal maintenance things (polishing my nails, brushing my hair) and listening to soothing, feel-good, quiet music. Before I went to sleep, I would journal for 10-20 minutes about my day, what I was thinking about, ect., NOT while in bed, somewhere away from where I slept. I also stored the journal away from where I slept. I would then get into bed, turn off the light, and begin some simple in through the nose out through the mouth breathing exercises while envisioning my breathing pushing negative energy out of my body and filling it with good energy, usually illustrated in my mind with contrasting colors (black for bad and purple for good or some such), concentrating on nothing but my physical body and trying to relax each segment as I went, taking my time on each piece of myself. I was usually passed out by the time I got to my hands or knees. If I wake up and feel disturbed, I would journal for another 10 minutes before starting my day, usually writing down what I remember of my dreams and what my hopes and fears were for the day.
I'm sorry that was so long, but this has been a huge help to my problems with sleeping. It's something I developed for myself by just identifying my stressors, every little thing, and by keeping in mind that I cope well with writing and drawing in terms of getting things off of my chest. Storing my journal away from my bed was key, though. I know all this sounds a little hippy-dippy but it really worked for me. I hope you sleep well tonight and feel good when your head hits the pillow.