If I ovulated last Thursday thur Saturday and started my period today and had unprocted sex today what are the chances of being pregnant? Should I take next choice to stop pergnancy? I am 24 yrs old and I have a 18 month old baby and do not want another baby right now.

If you are not wanting another baby why are you having unprotected sex. Yes of course there is a chance of pregnancy, no one can say 20 or 50 percent, too many other factors, including just luck.

And of course the longer from the sex you take it, the less effective it will be also.