Could this be implantation bleeding?

My periods are 32 days apart rather then the normal 28. My periods last about 5 days, and start out light and heavy and end up light again. Well, This month, I had unprotected sex.  I have used "period calculators" on the websites to give me an idea when I might start, and so far they have been right.(Not saying they are actually honest) One said I was fertile the days I had sex and should start on the 29th, but I started on the 24th, but my period was different it lasted two days, and it was just a randoms spots all through out the two days, I thought it was my period and I would wear a tampon, and not to be gross, there would be a little bit of blood or not at all, but it only lasted the 24th and the 25th and stopped, it was a brown color, and I didn't really have any cramps but today and I didn't spot or bleed.  So could this be implantation bleeding, and if so, when should I take a home pregnancy test. I'm a little bit excited, but scared at the same time.

Thanks!