am i pregnant? took i pill after precum entered vagina

hello doctor,
please help me as i am very scared and confused about my condition.
On 15th of july i was making out with my boyfriend but v did not have sex..his pre_ejaculate did come in contact with my vagina when he rubbed his penis against my vagina and it might have entered the vagina also...before this he had mastubated twice and ejaculated aswell..i was very scared about few sperms entering my vagina and making me pregnant so i tool an ipill on 16th... so basically i took the ipill after 30hrs.. my last period was on 28th of july ...also i did not get any side effects of the ipill...uptill now no bleeding headache nausea, has it worked? please help me i am very tensed..im just 19yrs old ....what are the chances of getting pregnant? also when should i get a urine pregnancy test done?
please help me as im very scared,, your support in this will b very gratefull..thank you..please reply as soon as possible..