pregnancy with clothes on..?

i had my last period on the 14th of november. i don't calculate my cycle but i usually have my periods between the 11th and 14th of the month and it lasts for 5 days. On the 7th of december, i and my boyfriend were together but we did not have sex.infact we just moved over each other and touched.  i wore a skirt but did not have panties on, while he was in his t shirt and shorts.so his penis did not come in contact with my vagina. now i'm a bit concerned because my period has still not come and its usually rather regular.i'm still a virgin too..so could i be pregnant...no penetrative sex...cllothes on...missed period..where does it all end???