If you haven't already I think you should look into Astral Projection and OBE's. This is a common thing in Astral society. I believe that when we sleep, we are somewhat separated from our physical bodies and existing in the spiritual realm. Astral Projection trains you to shift your awareness your energy bodies (spirit) and have full conscious awareness in the spiritual realm. You put your body to sleep and you become conscious of you energy body/s.
"Sleep paralysis" is very common. This occurs when you are in the transition phase. If you are consciously trying to project, this can happen if you can't let go of your ego or your fear of "losing your body"/Death. Many people experience this without ever trying to actually leave their body, and it can be a terrifying experience.
It can be addressed by simply asking for peace. If you ask God, or your Spiritual Guide to help you and take away the fear that you are feeling, it will happen. At that point you will either go into a full projection and leave your body or you will wake up in the physical.
As for the individual that you felt was there with you... Everyone has a spiritual guide, or "Guardian Angel". That may very well be who you sensed. Many people that have their first Out-Of-Body-Experience return to report that their guide was waiting for them. Your spiritual brothers and sisters very much want you to ascend and discover truth, and it is not uncommon that they will be there to guide you and help you as you become aware of your spirit.
However, there are many types of spirits, just as there are people in this world. It is important to note the "vibes" you sensed from this person. If you seriously felt that they meant you harm, then they may have been there to try and stop you. This can also be resolved by asking for God's peace and protection, and demanding that this spirit leave you because you are protected by the white light of the Holy Spirit.
I hope this response has helped you some
Peace and Strong Life,
Matt