Hello and thanks for your query. I understand that you are worried about the possibility of pregnancy after a non-penetrative sexual encounter. Since there was no penetration of the penis into the vagina and no ejaculation, the chances of pregnancy are negligible. Moreover, you have also mentioned that the encounter was the day after her period. So, she would definitely not be ovulating then. Also, you have stated that she took a plan B one step pill. so, considering all these factors there is no chance for your girlfriend to get pregnant after this sexual encounter. You needn t worry and can put your mind to rest. But next time, in order to avoid all this tension, don t forget to use proper protection befor any sexual act. Regards, Dr. Jonas Sundarakumar Consultant Psychiatrist