Although foamy urine may be sign of serious kidney or liver disease it doesn't have to. Foam may be sign of protein(in case of kidney disease) or bilirubin(in case of liver disease) in urine.
My urine is almost always very foamy. It concerned me for some time, so i did blood and urine tests and they were fine. Neither protein nor bilirubin was found.
I suggest you to do the same if it concerns you, but i think you shouldn't worry.