Becoming more attuned to such things is often a bi-product of astral exploration. Exploration, first-hand study, etc. simply opens your mind to such things, and with that comes a deeper awareness of energies, and the way that all such things work. Thus the new ease with working spells and other such practices.
As for the gate... well, what was the tug that you felt? What was the intent? Examine the situation, what your intuition tells you about it, etc. All of the answers are at your feet, so to speak.