My hind waters went with my last (planned homebirth), DD3, I felt a bit of a twang sensation when I was lay in bed and had a slight gushy/trickle.
Bit more, but not vast amount on standing. I was told that if you lie down for a while then stand if more trickles out it highly likely to be your waters its referred to as 'pooling' I think?
How many weeks are you? And if you are having a planned homebirth, they should come to you and check, I rang the unit and was told to go in until I advised them that I was having a homebirth so send someone out to me!
They do smell different to wee, sweet/oaty and straw like colour. If you put a pad on and walk around if it continues to trickle out save the pad for the midwife to check, my midwife smelt mine and gave it a good old squeeze and declared, Yep, that's your waters! 
Hotpink has given a great explanation of hind waters, which was the case for me, it soon became more obvious as I kept having to change pads,and each time baby moved and when contractions eventually started more gushed out!
Oh the other MASSIVE indicator for me when I really started to think they had gone was my bump had dropped a lot and there was a noticeable dip in between my breastbone, my belly looked like a deflating balloon!
Good luck x 