When I played in a much louder band with no monitors I used one of those Rolls Personal Monitors. Ran my mike though it so I could hear myself sing. A huge help. (One one model you can also run your guitar though it as well but I didn't.) I usually used only one earbud, leaving the other open to hear the rest of the band, with or without an earplug. Not perfect, but it's a lot cheaper than an in-ear system.
Current band has a nice PA. In theory I shd be getting bass along with vox through a monitor feed, but often as not there's just no time to get everyone's mix set up well. I guess if you had one of those fancy Presonus boards you could preset it all?
Anyway, back to my OP, more and more often your amp is nothing more than a barely audible stage monitor. Even though it all makes sense, I do miss the volume behnd me sometimes. Thankfully, we get a few outdoor gigs.
PS - I have to admire PBG's caution in the bedroom. Learning from experience...