My experience changed after the update. Did I lose progress?

No, your level and progress are safe. Update 1.16 changed how much experience each level needs, so your experience was converted to the new scale. Your level stayed the same and your progress bar is at the same point: if you were 70% of the way through a level, you're still at 70%.

Your profile now shows experience as numbers — how much you have and how much the level needs. They're shown in a new way, so they may not match what you saw before.