Noob question: Can someone explain why my btc/day dropped about 40% at the same hash rate I've always had?

I've been mining off my RX580 in compute mode for a while and noticed these past couple of weeks instead of mining at about $1.01/day I'm now at $0.64/day. I don't believe my hash rate has changed at all. Mining at about 27.5MH/s. I'm guessing it has something to do with the difficulty changing/price dropping?

Submitted August 25, 2018 at 07:01AM by rikkuna http://bit.ly/2P026Oj