decidual bleeding or early period?

ok. so my las period was january 7-11. i had sex on the 23rd of that month and about 6 days after i had some bleeding. it started off light but went heavy like a normal period and only lasted 3 days. (29-31) after that i had light brown spotting for a few days. i always know when im gonna get my period because i have serious pms. sore breasts, major cramps, lower back ache, but this bleeding was different. it just kinda happened and then kinda went away. i never cramped or anything. but about a week of two after i started cramping when my actual period was due and i thought i was gonna start but i never did. i was wondering if this bleeding is decidual bleeding and could i be pregnant?

[penswriter]

if you had sex yes it's possible you're pregnant. take an hpt.