Missed period but i have been having alt days of wiping red blood, brown discharge or nothing. +preg test. could it be implantation or etopic preg?

No, and Yes: Unlikely that this is implantation bleeding as implantation bleeding were it to occur, typically occurs 6 days after intercourse, if it occurs at all. It could be an ectopic pregnancy, the chance of that with no other risk factors is about 1 in 50. Definitely if that's a concern, make appt to see a doctor and get a blood pregnancy test and possibly an early ultrasound to make sure in uterus.