Among the things that you know with groundless certainty are that you are not your own creator, not the author or originator of your being, and also that your own being, that which is you in the deepest end most eminent sense has not arisen contingently but goes right down to the very root of being. These two knowings are contradictory in a way that doesn't trouble you. On the one hand everything that is is ultimately impersonal, that it 'does' its being without any account or distinction of individuals, and at the same time everything that is is utterly personal, with a personality of which you in your unknown depths are the perfect exemplar. Another way of saying this might be that you are not contingent but everything you know and experience is perfectly contingent. Perhaps this is what is meant by being 'necessarily contingent'. This is a notion which is almost thinkable, so take the thought and see that it has two sides like a coin, depending on where the stress is placed.