[art_fan_12]

olivia - you state that its not until you start to question the sensation, that it seems wrong, if i read this correctly. its very important for you to analyze exactly when the feelings of negativity start. do they start before you question it, or only after?
if it is only after, then i would suggest that the negativity is not associated with the feeling, but actually is directly in relation to your skepticism of whether or not this is a positive thing. in regards to the feeling of heaviness, i would let go. remember that you are in full control. by letting go and letting yourself experience this sensation, you are elevating yourself to a higher spiritual level. if you think about it, it is more than likely the sensation is that you are so connected with your astral/light body that you actually feel the physical form as a weight. it starts from your head because generally almost everything starts from the head for us - due to the location of the pineal gland.
remember that a negative - and even a positive - entity cannot take control over you if you go in prepared with the knowledge that you are not allowing anyone to interfere. you are not granting permission.
before you fall into the heavy meditation, after you have settled and quieted yourself, i suggest first imagining yourself surrounded by a shield of white light - imagine that while it does not confine you (ie you can send your energy out of it), nothing can get in without your permission.

also, id suggest once done, record everything in a journal. everything from your physical senses and sensations, to of course what knowledge you receive. if you do not receive any specific knowledge, then know that the meditation acted to resolve something in your life, you cleared negative energies from within (can be caused by stressful situations and worries).

a second option is this... you said you feel the pressure and you are immediately(?) associating this with like wearing a hat. however i do have a question, have you ever noticed whether or not the pressure is pushing down on your scalp - or is it possible its pressing up on your scalp? from the inside? if its right there at the top it might take some discernment to figure that one out - but i would suggest then that if it indeed feels like its actually coming from within, then this is your energy manifesting and exuding out of you. if you do not release it, it will cause physical symptoms that can lead from headaches to queasiness, and of course fear and anxiety.