Urine or amniotic fluid?

Had an ultrasound on Thursday at 37 weeks and was told my fluid was good. I have had small leaks here and there that I know are urine but yesterday morning & this morning when I woke up my panties were a little more damp/bigger wet spot on them. I do wake up to pee about 4/5 times a night and I feel like I leak urine throughout the day after using the restroom but I just wanted to know, how can you tell the difference? Would amniotic fluid be coming a lot more?