Do some people give off "single vibes"?

Recently, my boyfriend and I split and all of a sudden there are a number of my male friends who are very interested in me. These are guys that have previously shown little or no interest either sexually or romantically.

So, my question is this: Have I released some kind of “single hormone”? Is the behavior of a suddenly available, potential mate so wildly different from that of an unavailable person? Is it just pure coincidence?

I promise this is a serious question. I know it sounds silly, but I am honestly curious about this. It’s just so strange and sudden.