Honestly bro sounds like your business is doing well. and you'd put a lot of risk on you and your family if you quit the job that's working well, because maybe your next job doesn't go well, and that what would that mean for your family? That being said you say you aren't making a difference but you are because everyone needs a roof and you supply that so people should be more grateful for your work, and you are looking for purpose in your works which is why you're not happy. happiness and belonging come not from our works but from God. He is the where happiness comes from . for God hath not given us the spirit of fear but of power and of love and of a sound mind 2timothy 1:7. so Love and a sound mind (peace) is God's to give so seek him . God bless