Feeling pregnant

Me and my partner have been trying to conceive for 3months, I had a normal period on the 23rd-26th may on he 6th-8th June I noticed brown discharge when wiping nothing major, according to glow I was due on the 20th June but nothing done a cheap test yesterday everyone has said it was a faint positive, this morning I done a first response and it's negative, my nipples are sore, my appetite has changed some cramps but nothing like period cramps, emotions are all over the place, I have a heavy feeling in my stomach feeling sick constantly tired really confused