When should I test?

So we are not trying for another baby YET. I have a 7 month old son, who I exclusively breast feed. Two weeks ago we were on holiday and things got frisky for the first time in MONTHSSS and we just wasn’t prepared so one thing led to another and he pulled out, quick and easy yano. Now, yesterday I got what I thought was my first “period” in over a year to realise it didn’t even fill a pad and it has now stopped, could this be spotting? It didn’t even cross my mind until my husband said “are you sure it was a period” could this just be the Red Devil creeping back in or what? Thanks you sexy ladies