Light and short period... could I be pregnant?

The run-down:
- Hubby and I have been TTC baby #1 for 14 months.
- I am 25 and he is 30.
- My cycles are regular (28-30days)
- I had a short luteal phase but after taking B6 it is up to 12 days.
- I have not been stressed or sick, so that isn't the reson my cycle is weird this month.

My question:
What I thought was my period came on cycle day 28 and I know I was 12 dpo (days post ovulation) because I've been using OPKs. However, instead of my 4 day, normal, moderate-heavy flow the bleeding was much lighter and only lasted for about 36 hours. It was definitely more than "spotting" but it was only enough to need one "regular" tampon during the day and one "light" tampon at bedtime. The color was also unusual, it's normally bright red but this time it was light brown mixed with some pinkish-red stringy mucus but I did have ONE "gush" of dark red blood while peeing but then it went right back to brown/pink mixed with lots of clear cm. I took a HPT at 10dpo and it was neg then 2 days later the weird period started and I haven't taken another test yet. I feel more nausea and bloating now than I did before or during the bleeding. Has anyone experience a light, short period and found out they were pregnant? If so, how long after the bleeding did you get your positive result? I would love to hear your personal experiences! Thanks!