Could I still be pregnant??? Experience please..?

First- I'm not on the pill... I had unprotected on the 6th of this month and then started bleeding pretty much like my period on the 14th (prior to that my period had been on aug.17th). the bleeding was kind of abnormal though... brown mixed in.. It has now been about three weeks and I am very congested/sneezy/have had a sore throat and headaches off and on..I never have headaches! I'm also tired pretty easily... My appetite has decreased too/no changes/BUT definitely increased discharge I've noticed for awhile.. do you think there's a chance I should take a test? I don't want to worry about it but these little symptoms keep coming up.. Thanks:)