The epicenter was at Julian, which is about 20 miles east of Escondido (which is about 20 miles north of San Diego). If you lived much further away and were moving at the time it happened, then you wouldn't have noticed it. But if you're sitting down, then you would have felt some jolt that you could have mistaken for a large fart. There was about a second of minimal shaking, again, only noticed if you were sitting down.
I was surprised about the earthquake alert for 5.2 magnitude of a single jolt. I didn't think it warranted an alert, tbh. Kinda used to magnitude 4's and 5's quakes as a norm.