Is Pregnancy Possible Through Non Penetrative Sex?

i have a guestion, i did not have sex this day, but he did have sperm on him when i was going to sit on him i did not know that he ejectulated but he covered his sperm with his hands and told me that it did not come in contadct with the outter part of my vagina. therefore i dont know if i sat on it accidently or if i did not. it been 1 week and 6 days and i threw up one morning and felt aching all day and upset stomach, but to keep in mind my sister did have a stomach flu but we did not share food or drinks. i had my period on the 13th of jan. and this happened on jan 27th, i am very scare i am 19 and i dont know what to do, what are my chances of being preguant