birth contril pil, 'now'? Or not?

Hello,
I miscalculated if it is save or not to make love, I think. But I am not sure now.
So I hope someone here can advice me about going to the doctor now to prevent pregnancy or not. I do not use the birth control pil for medical reasons.

This is how it is:
On the 13th of this month (in the night of 12/13) my period started, and it lasted 5 days. In my period the last two days (16th and 17th) are 'very' light, almost nothing on the last day. So I do not know how much this counts as period days. My last cycle was 31 days.
I made love on the 22th, which was yesterday.

Does this mean that I might get pregnant as soon as my ovulation starts? If so, what is the most wise thing to do now?

A morning after pil might be an option, but would it also be an option to use a sperm killer kind of medicine or something? Since My ovulation almost cannot have happened yet, it would suffice to make the sperm harmless? Or would it not?

I hope for a reply soon, so that there is enough time left to arrange the things I sould do 'today'.