Could i be pregnant again this soon?

i just had a baby boy 4 weeks ago. my postpertem bleeding stop bout two weeks after i had him. well on june 27,2011 me and my boyfriend was messin around by him touching his penis to my virgina but he didn't go in me and we didn't have sex either but we were undress from the waist down i think he may of pre came or came near my virgina two days later i started some very light spotting didn't less but that day well tonight my hips are hurting so bad i cant even describe the pain whats gong on