Can you tell your pregnant early on?

Madison
I had sex with this guy a few weeks ago. We used a condom, I'm not sure if he pulled out when he finished. I haven't had any signs like morning sickness or anything and I'm not supposed to start my period till tomorrow but I'm a very paranoid person so I was just wondering if (those of you who have been pregnant) you knew you pregnant before you had it confirmed it and if there were any signs when you were SUPER early that I should be looking out for. I know I sound silly, I just get scared about that kinda thing.