i have experienced the eye thing as you have, i personally find it a mental thing, but its also very physical, for instance you may feel your dream body and your real body at the same time as you try to open your dream eyes??? this is where you probably fucked up, i do find this very hard to explain but ill try.
its hard to put into words, but you have to give up awareness of least one body, primary your physical.
its like a game of tag of war, you may feel the pull of your dream body and the pull of your body in bed, what you have to do is become more aware of your dream body senses, tune into your dream body more then your physical, this may be unrelated but it sometimes works in my regard, i once read in a real old astral projection book;
that the silver cord can pull you back to your body if your not careful, his advice was to get away as far as you can from your physical body, and you wont feel the pull of the cord so much, i kinda carried this over to my lucid dreaming practice and it works, alot of people become lucid in there bedrooms dont they or find them selves there when they wild i hope i helped in someway