You might be probably having sleep terrors which is common around your age caused by bad sleeping habits, going to sleep very late at night, not having day time nap, might have witnessed a terrifying incident and not able to come out if and stress due to daily activities. You might have had an occasional sleep paralysis episode. How severe do you think this is interfering in your studies or routine daily activities? Do observe for some more time and follow few of healthy sleep habits like a regular sleep-wake up cycle, going to bed as early as you can, avoiding excessive coffee/tea, spicy food at night times. Regular exercises or stretches are beneficial. A warm bath, soft music and gentle body massage before sleep can put you to sleep without much disturbance. If it is continuing, consult your doctor for a sleep study and evaluation. Take care and post your thoughts.
Thank you for the reply.
I have previously had hyperthyroidism when I was younger and because I have regular blood tests as a result it's likely that it's not the cause of an illness. I also don't seem to have any other symptoms that are not sleep related.
A sleep neurologist sounds like a good idea though...I just have to find one.
Some of what you describe does sound like descriptions of sleep paralysis. An occasional episode shouldn't make you feel so tired every day no matter how much sleep you get. It may be that you have more than one thing going on. Life and it stresses can cause odd things but I wouldn't just write this off as stress. And certain illnesses can cause fatigue (hypothyroid, diabetes, anemia).
If you have sleep disorders and/or your sleep stages are out of kilter, you will feel tired during the day. A sleep neurologist could be helpful, and will probably want to do a sleep study to get a full picture of what's happening while you sleep.