Condom broke, next morning I got my period - am I pregnant?

Your period is the lining of your womb coming away, when it is not needed to nourish an implanted embryo. Therefore, there's nothing left to implant into, if you've just had a period.
You got your period, so you weren't going to be pregnant.
You have no lining left, so it couldn't implant, even if pregnancy was still possible.
You then took Pan B, which is usually good at preventing pregnancy, even when pregnancy IS possible.

Plan B is a big dose of hormone. It can make you tired, run down, moody or depressed, bloated, give you backache, cramps, bleeding (which can get heavy) & various other symptoms.
It will likely delay your next ovulation (release of an egg), & that will therefore likely delay your next period by a week or two. It may also be heavier or lighter than normal periods.

Oh my how we can make our body have symptoms when we want to believe it. You would never have any symptoms of pregnancy yet. You had your period, that says not pregnant, but to be sure you took plan b, that says probably not pregnant, but somehow you are still thinking you're pregnant. The spotting is from the plan b and your period will probably be late too.