Dear Welcome to HCM We understand your concerns I went through your details. These are obsessive thoughts and you should learn to keep away from it. Using an used toilet paper cannot impregnate you. Sperm cells do not live in outside temperature and especially in unfavorable situations. Over and above you were ovulating at that period. No chances of impregnation. You know about these things and still you are suspicious and that is what you should change. Logical conclusion and agreeing to an expert opinion should be your habbit because of health anxiety concerns. I suggest you to consult a gynacologist. Ask the above questions. Get satisfactor answers. Once your doubts are clear, bury the doubts so that they never crop up again. Bury your obsessions. These obsessions always try to come in different ways, and therefore you have to change the whole attitude. You may consult a psychologist for attitude related therapy. If you still need my assistance in this regard, please use this link. http://goo.gl/aYW2pR. Please remember to describe the whole problem with full detail. Hope this answers your query. Please feel free to post follow up queries. Available for further clarifications. Good luck. Take care.