And your friend would have killed you. A drowning person isn’t thinking rationally. They will grab you and hold you under the water with all of their adrenaline fueled strength to try to stay above the water. If someone is drowning you never get in the water with them unless you are specifically trained for that and even then it is a last resort. Drowning is one of those situations where if you just run in and try to help without thinking then the ambulance just winds up hauling away two corpses.
What you should be doing is finding anything that floats and throwing it to them or finding something long that they can grab onto so you can pull them to shore. For example tie a couple towels together to make a rope or dump out a cooler and throw it in for them to grab.