I'm 22 and I have fibro, IBS and interstitial cystitis. I want to come off my meds are there anyways I could treat these illnesses at home?

Maybe. While there are no home medications you can take, there are other behavoiural modalities of treatment you can use such as dietary changes, change in sexual habits, using condoms, increasing water intake, and avoid certain stressors to the bladder such as alcohol and coffee.
Unlikely. Can go on a bland diet, avoid acid urine producing foods and beverages, take prelief or Tums (calcium carbonate) to alkalinize urine. Avoid stress. You almost certainly will need to remain on meds. And hope it improves on its own. You can always try and taper meds if you are presently symptom free. Some patients get relief from cystoscopic bladder hydrodistension, or DMSO cocktail instillations. Obviously not at home.