Blood in urine / excersice

Hello,

I am a 31 year old female.. Stared having problems about four years ago.  First symptom was that I noticed blood in my urine after exercise, especially after exercising large muscle group ex legs   (such as running).  Found this very odd b/c I been I have always been athletic and exercised intensely since I was young.  After a couple of years with no answer  I found a Nephrologists whom suspect IGA nephropathy.  She came to the conclusion bc blood in urine and also had some protein.  I took blood test every three months and then the blood and protein disappeared.    I have mentioned to her and other doctors that the blood in urine rears its ugly head after I exercise, however all the doctors that I have informed sweep the symptom under the table.  

So unfortunate, I stopped excising, bc I was unsure if I was causing more harm than good.  The blood in urine disappeared for aprox over a year with no exercise.   Until last weekend I was coaching softball holding different squatting positions while instructing.  Do to the fact that I am out of shape my legs were fatigued and sore... Then of course it was back the blood appeared again, it only it was only in one urination however it was extremely visible. Plus when this happens I feel a little sick and worn out? It seems to happen more when my muscles are pushed to the point of fatigue

My question is what is causing this.  Is it normal with Iga Nephropathy?  I miss excising, if i just say to heck with it and exercise am I causing more harm?  Ps. I also notice if I don’t eat a lot when I exercise my blood sugar drops fast.

Thanks for your help, unfortunately I have nowhere else to turn, no one has been able to give suggestions or advice

Sheri