Tenants rights when roommate is also landlord

[suzcar]

I have a roommate that owns the house that we live in. Everything is split down the middle (rent, ultilities, etc). Her boyfriend moved in a month ago with his dog. I feel it is only fair that everything now gets divided by three.
Being how frugal and selfish she is - she doesn't agree with me. "A deal is a deal" was her response.

Also, she requested 45 days notice if I was going to leave. We both decided back in mid August that the end of September would be when I was leaving. So when I signed the extention (to the original 6 month lease which expired in August) - I wrote on the bottom that my last day here would be September 27th.
She never said a word.

I just paid her rent and subtracted those 3 days. Now she is telling me that we have a "month to month" agreement and I must pay the entire month plus all utilities even though her boyfriend is now living here.
If I gave her 45 days liked she asked - why do I have to pay for those 3 additional days?

You do not owe for the 3 days. The required amount of notice on a month to month tenancy in NC is only 7 days (not 45). It is not a term state where notices must be given at the beginning of the month and must end at the end of the month. Look up and quote NC General Statute 42-14 for her.