Advice?!

Mercedes • Mommy of one amazing little boy and girl and #3 on the way 😍
Got these the past two days and then went in for a blood test yesterday and I was supposed to get the results back this morning so I can make my first appointment. Still no call so I called them to see and they said to try back this afternoon. I wasn't like this with my first pregnancy. I got the one positive and just knew and got my appointment. This time I am nervous because of so many people posting about chemical pregnancies. I also took an EPT this morning and there was a very faint line. I am still just 11 DPO. I feel that I am pregnant but I don't know if it is because we have been TTC and I'm wishful thinking or because I just know. 
Can anyone give me more info on what a chemical pregnancy is? Or should I stop stressing and just be happy?