Hello I Am A 40 Year Old Male Who Is

Hello I am a 40 year old male who is currently prescribed oxycodone 10mg tablets dosage being six times a day. last week I took a urine test, and I got a false negative result. I take the pain medication for a past hip injury that cannot be corrected with any procedure. I also suffer from chronic kidney stones, and have had multiple laser endoscopies, and lithotripsy's. After suffering with stones for so much time, and doing research, now. when I start to feel like I have a rental stone I will do a flush as I was told this can help me pass the stone easier. My flush consists of, flomax, large quantities of lemon, and cranberry juice, large quantities of water, also niacin pills,, olive oil, and vitamins c pills,. My question is can this combination cause a false negative for opiates, as I cannot explain this any other way. I don't want to be prejudiced like I'm doing anything illicit, or abusive when I know I am not. If anyone can aid and assist me in this injury it would be greatly appreciated, and I thank you in advance.