Hello , Iam 62 Years Of Age, Ive Been Having

Hello , iam 62 years of age, ive been having a sharp pain on the left side more towards the stomach not the side. My family Dr. said it could be an inflamed colon ? but I also have interstitial cystitis which is flared up , I do have a lot of blood in my urine seen under mircroscope only he did not think its a kidney stone. iam confused weather I should go to the er. or not I cant see my stomach Dr. until the middle of June. so I guess my question is the pain comes and goes is it that important to go to the er. I hate waiting there when the pain isn't constant until I see a stomach dr. there next week. I guess im just not sure what iam dealing with . I do know when I get a flare up with the IC I can get referred pain in the back and stomach. I was trying to figure out the pain between a kidney stone or colon ? thankyou for your time ,, Marie