Could this be a sleeping disorder?

Im 20 years old and since about my 10th grade year ill wake up every now and again in the middle of the night and see spiders crawling on the wall or in the bed. I'll jump up and flip on the lights and as i wake up more i see they are gone. I've done it alot lately to my boyfriend in the middle of the night and he thinks its some kind of sleep disorder. Most of the time its spiders but ive also seen monkeys or people or cats. I know it sounds funny but it really does freak me out. What could it be?