Magical work of negative beings in my room

[Bring4th_Austin]

To put what others have said into other words - something that might be worth considering for you or anyone else in a similar situation is the idea that your perception while in this state might not be reliably tuned to some objective reality. In other words, what you perceived as an entity, as a symbol, and as a circumstance within your bedroom could have been an experience given to your by your own unconscious mind. I think this is an important consideration, because (as I understand it), to have reliably keen and accurate insight into unseen realms is quite advanced work.

For instance, as Ohr Ein Sof said, the pentagram is generally a positive symbol, and the general negative connotation is a bit of a cultural misapprehension surrounding the Satanism scare. Positive magical systems have been using this symbol long before the modern negative connotation, and it benefits from a long history of magical reinforcement. Ironically, the ritual that first comes to mind for protecting your room is called The Banishing Ritual of the Lesser Pentagram (or Lesser Banishing Ritual of the Pentagram). This ritual was effective enough to offer protection for the Ra contact and Carla, Jim, and Don. They practiced it every day in the room where the contact was held, and Jim still performs this ritual every morning in his living room where channelings still take place. The crux of your question seems to be focused on this symbol being perceived as negative when it has strong white magical connections.

I offer this both as a practical suggestion for a magical ritual, but also as an example that your perception while in this meditative state may contain more of your own unconscious mind's creation than something "real." And that is not to denigrate the nature of such an experience, as both can have real effects on our realities. And in such a realm, lines can be blurred between internal and external realities, so both understandings can be applied, but the potentially personal nature of such an experience shouldn't be ignored. The likelihood that what you saw and experienced is an aspect of yourself asking for your attention seems relatively high.

I would also echo the caution in Sacred Fool's post. Intentionally approaching what you presume to be a negative being without an established magical practice of protection and without direct guidance or aid from others with experience is a recipe for energizing the potential for more troubling situations - whether generated internally or from an external source.