Many people complain of brownish discharge p/v after getting depo shots. Depo provera is a progestin and Irregular bleeding (spotting) and/or prolonged bleeding (like a continuous period) is actually a completely normal side effect.
Also, the risk of pregnancy in a sexual contact without ejaculation is very low. Depo-provera has a failure rate of less than 1%. Hence, the possibility of pregnancy is down low. But still to rule out the possibility, I would suggest you to go for a urine pregnancy test in few days (around 2nd week).