My little 50s bathroom is lined with tile, so I play in there all the time. Love the natural reverb.
But, as far as singing goes... yeah, hearing yourself is quite important. If the bathroom is what helps you, go there (no pun.... OK, whatever...).
You might also try putting an earplug in just one ear. It helps. I used to do it often at gigs with lousy monitors.
Overall though, let me just say.... don't get discouraged, and dont expect everything to fall right into place. I know you said you're fairly new to this, and well, singing takes some time to learn, just like guitar. And doing both at the same time is another whole skill set. Once you learn what those sound waves feel like rippling through your head, you won't need to hear as much. Especially when you play in the same keys frequently.
Not everyone is a natural-born Richie Sambora!