How can I get over my stage fright/sing in the house when people are there and not get nervous? (Description)?

I'll wait for an opportunity for somebody to leave and then I'll sing.
Problem is, no one ever leaves, and if they do, it's only enough time
for me to warm up. It's getting out of hand, I can't skip singing all
week! I need to practice everyday.

I don't like rushing my voice to sing quicker because I have a short
amount of time before someone comes back, plus it strains my voice
because I kind of oush harder to get my singing in. I need to sing
with people in the house (I can do it in my room with the door shut)
and not care. Any tips?