could i possibly be pregnant? or is there a problem?

hi. i was on the pill for exactly one month in april and after getting off of the pill my periods were different than before. i noticed i still had a lot of the side effects that i had when i was on the pill... i had very bad cramps, really sore breasts, and a little nausea as well as fatigue. last month my period came at the end of the month and stayed on for exactly seven days which is the same amount of time it always lasts. this month, i had soem spotting right after sex... just a couple of very light pink drops. then it stopped. the next day i had a few light brown spots and it stopped again. the next day, i had what i thought was my period starting: it was much lighter than usual and it was pinkish-brownish also (still no red blood) and finally it completely ended the day after (or so i thought). the day i was supposed to start my period (exactly seven days before the end of the month which is the last possible day for me to have a normal period) i had absolutely no bleeding. and finally today (the 26th of july) i had no real bleeding at work this morning except for some light discharge mixed with brown blood only noticable when i wiped. but when i got home and after a nap i used the bathroom and blood came out. and when i wiped, i saw dark reddish brown blood like a real period. but soon after... no blood came out on my pad and when i use the restroom, i only get small amounts/ or what looks like spotting on the tissue.

anyway, this whole time i have been experiencing much more sleep than usual... i find myself able to take 5 hour naps and return to sleep at night only an hour or so after the nap. and when i awake to go to work, i am still just as tired as if i didn't get enough sleep. i am nauseas sometimes as well as usually constipated. i feel pregnant but have no breast swelling or sensitivity. i have been experiencing excess saliva as well. can implantation bleeding be like this? is it possible for me to be pregnant?