I'm probably gonna have to start singing in my band due to the lack of singers where I live.

I haven't sung that much, I probably stink and I'm afraid what my bandmates will think of my singing, I'm pretty self-conscious; especially when it comes to music.

I want to be able to sing without any fear/doubt at band practice and to feel comfortable about it.

Any advice?
iv had to do this before and if your other members know the situation then they will know not to expect great things. but you never know you might surprise yourself. just go for it and enjoy it and you'll be fine
The only fear you have is the fear itself.

If you don't feel comfortable with your own band, then you need to work on empathy with the members. Because they are your friends and you have fun together playing music.

And ask for their help and their opinion about what you can improve in your voice. Grow as a band and don't worry about being judged, that's not the point.