What Are The Chances Of Pregnancy Through Non Penetrative Sex?

Last month i had my periods on 23rd.on 22nd of feb my boyfriend just touched his penis to my anal side but it did not get inside.my vagina was wet at that moment.and nothing else was done.there was no ejaculation from his penis.I still did not have my periods this month.can i be pregnant? please help me...i am really tensed !!!