I just want to clear up a few things. First of all, the experience is normal for a beginer to astral project experiences.The second thing is that astral projection is happening each time the physical body sleeps.
This might sound weird because most people on the Internet do not say so. However I am insisting on it, stating that astral projection is happening every time the physical body sleeps but we say it is astral projection, when a person becomes aware during the separation process of the two bodies.
Lucid dreaming is when your awareness is shifted over to the subtle level while the astral body is still inter-spaced into the physical one but in astral projection, the astral body de-synchronizes from the physical one.
The paralysis occurs when you become aware of the two bodies and they are not in perfect sync and that can happen both when they are about to separate and when they are about to be fused into each other.
The logic in this is that since astral projection is happening every time the physical body sleeps, then there must be a psychic mechanism in the psyche which operates the separation and then re-unification of the two bodies. And this also means that if you could monitor that mechanism you could decrease the frequency of sleep paralysis experiences and have more astral experience which are favorable.