Astral Spider Problems

Basically for a few years I've been seeing this really weird black spider like orb. I only ever see this thing at night time and whenever I see it, it has this almost draining effect, as if it is literally sucking the life out of me I've come across a similar thread with an accurate illustration of the entity I've been seeing http://www.unexplained-mysteries.com/forum/index.php?showtopic=217774 In my research I've been coming across threads about things called astral spiders and I'm not sure if this actually one of them but I can see how it could be mistaken as being one. Some times around my house ill see something in my peripheral vision drop from the ceiling all crawl about but I can't quite make out what it is. I only started seeing this thing in my mid teens and the first time I saw it I literally almost passed out, I really couldn't believe what I was seeing. I'm not sure if this is linked to shadow people at all but I really don't see the reason why this creature feels the need to observe me so much, it's really creepy. I have no existing medical conditions at all apart from asthma which I highly doubt could cause such a hallucination. The only stimulus for this sighting that I can think of is stress. I only really ever see this thing when I'm stressed out or upset, its almost as if it feeds on negative emotions or something. I don't do any form of drugs or substance abuse nor do I really deal with anything occult. If anyone knows what this is please tell me, any help would be much appreciate. Thanks for reading.