panicking! need advice!

Okay so I am usually pretty regular with my periods but I am now 13 days late. Last night me and my boyfriend had sex and straight after I had brown discharge so I am worried as I looked online and it said it could be a sign of pregnancy. I had a miscarriage about 2 years ago and I'm scared to go through it again with my new boyfriend.  Any advice would be helpful. Don't know what to do as I am scared to do a test.