Why Did I Miss My Periods Making Me Feel Bloated?

45 years old my last period was around August 19th and normal. September "brown" in color didn't last a day & basically wiped. October, same situation not a day long & brown in color wiped clean. No period in November. Now have gained weight in lower midsection, very bloated & full by uterus, breasts appear bigger, fatigue, some nausea... & have been experiencing flutters & spasms... I took 2 pregnancy tests.. as I felt strongly I was pregnant. (1 incorrectly) and both were negative (Took around November 12th). I have an appt to see my Dr.. and haven't done another home test due to the 2 negatives.