That is the classic "not enough head space". It is hard to get sufficient head space for one gallon of beer in a one gallon jug. Your picture shows some hop debris coming up with the krausen. This has the potential for plugging the air lock and blowing it off. The blow off can mess up what is nearby.
For the short term pull the airlock and stopper. Replace it with a aluminum foil cap that is well sanitized. Krausen which continues out of the fermentor will just flow down the side of the jug. Place the fermentor in a tub or bucket to contain the spill.
Clean the air lock assembly and rig a blow off tube. That is if you have the tubing on hand. If you don't have tubing the foil will be good until the krausen begins dropping in a day or two. Then replace the cleaned and sanitized airlock and bung.
This is how to assemble a blow off tube with your three piece airlock.
Fermentation produces heat. The warmer the fermenting beer is the greater the activity of the yeast will be. Your beer was probably fermenting 2°F higher than the ambient. With the ambient at 68° your just near the high end of the range for most ale yeasts. No off flavors from a too hot fermentation. Starting with the fermentor in a tote or tub with water will drain off some of the heat produced and keep the fermentation temperature close to to ambient.
Before your next brew we can offer more advice on temperature control.