freaking out

Water changes.

In the future, play around with altering the chemistry in a bucket, not in the tank.

The alterations in pH that are short term (ie, a quick dip) isn't as stressful as one that is there for the long term. A fish can encounter sudden, sharp changes that resolve themselves (ie, a pocket of deeper water that wells up, but only alters the chemistry for a short time).

Don't do a huge water change--you'll want to change enough to get the pH to a halfway point.