Pungent Urine

I am a 23 yr. old woman with cystisis. For the past 3 weeks I have had very pungent smelling urine and it is dark yellow.There is also some foam in it each time I go. I often have bladder cramping for a few minutes after I go. I have Cystisis...but I don't normally have all these symptoms at once and for an extended period of time.I know it is not a UTI...I have had plenty of those and the symptoms are not the same. Has anyone heard of foam in urine with Cystisis??