Pregnant?

So, on my app in here it says my most fertile day should have been the 10th. I didn’t have sex until the 13th and we didn’t use protection and he didn’t pull out. I’m not suppose to start my period until Wednesday, but yesterday when I went to the bathroom there was pinkish spotting. It hasn’t happened again since. My daughter is 4 so I don’t remember much about when I got pregnant with her, but that looked to me like possibly implantation bleeding? Is it possible for me to have gotten pregnant even tho it was a couple of days after I ovulated?