Why My Period Is Late?

Hi there, I'm worried if I am pregnant.My last period was on the 1st may...then I had another period in that same month on the 31st. Me and my partner are sexually active, so we have sex almost everyday unprotected but we use the pull out method. I had a weird bleeding on the 23rd of June which felt like I was on my period but it was a lighter coloured blood.However, I'm normally due on my period between the 3rd-10th of every month and I'm almost a week late???