brown discharge /pinkish spotting 6 days into pill packet. Had sex after 2 days with no condom. Pregnant?

I don't know about what your discharge could be but I do know that it is wise to use a back up method of conception for at least the first month when switching.

So is it possible, yes I think it could be or the discharge could be some minor break through bleeding (as that it appears to be common when switching between methods)

ermm, for the past 2 days ive had 'old blood', it smells a bit nasty, i can see that it is old blood, i had my period a week ago. it was a bit strange, not a normal period for me, i was very heavy and it lasted 3 days, the 4th i was completely clean, but the day after a few drips. and now this! ive been having a lot of sex lately. but im quite sure im infertile, because ive been sexual active for 5 years, with 18 different people, most of which i havent used a condom. i have no sti's or anything, i have a regular check up every 2 months. so what could be causing this? could i actually be pregnant? or is there something else going on down there? im 18.