Milk Supply Just Stopped

I started supplementing one formula bottle with my son on 7/18. AF decided to make her grand debut 7/20 (still going I might add)

and since then it has been a struggle to pump 6 ounces a day. Last night into the morning something just didn't feel right. Very rarely will my son wake in the middle of the night and for the past week (maybe two) he's maybe slept through the night once. I thought he might have been teething since he just cut 3 teeth at once so I've been giving him Tylenol to see if it would help but he would still wake so for the past three nights I stopped giving him the Tylenol and gave him a 4 ounce bottle instead. Last night and his morning feeding were my wake up call. If he woke during the night I could nurse him from one side and he'd be back in bed in 10 minutes, last night I had to nurse him from both; same with this morning. Then the final straw came at work when I pumped: 1 ounce at 10:00 AM and 0.75 ounces at 1:00 PM. Did my heart sink a little? Yes. For the first time in our breastfeeding journey though I actually felt relief. On several occasions since February I've been overwhelmed with getting just enough to the point where I would cry but I continued to push through it because I wanted the best for my son. I have tried everything besides standing on my head to boost my supply and nothing's helped. Am I sad that this journey's over? Of course. Was I worried that he'd have trouble going to sleep without nursing? You better believe it! But as I sit here holding him passed out in my arms my heart is overwhelmed with joy.