I went off the pill in September. I had a normal period in October and November. Two weeks after my period ended in November, I bleed again for about 4 days. I did not have another period or bleeding in December. I had sex on January 1st. Two days ago, I started noticing a faint brownish discharge when I go to the bathroom. Nothing significant to warrant a pad or tampon. Although today I did notice some clothing and tissue. Could I be pregnant?

Yes, pregnancy is possible.