The person who told you to remove your supplies must have missed every basic manager training session. As Nancy suggests, take a copy of that section of ADA to HR or to higher management and request a private area for testing and all reasonable accommodations you require, which would certainly include keeping insulin refrigerated. Put it in a different box..how would "uncomfortable" know what it is unless she went snooping in other's lunches? I am sorry this happened and you have to even bother with showing a law to your manager when basic commonsense and decency should have been sufficient.