Always The Worrier

Not exactly sure where to post this so here goes. I have 3 kids and we are NOT trying to get pg. My periods have been pretty whacky lately. I am actually starting to wonder if I am going into perimenopause. I am 34 and have a family history of perimenopause early in life. My periods usually were 30 days then 28 days. This month it was day 33. It was super heavy day 1&2 by the time I got to 3&4 it was pretty light. Today is day 5 and it is so light that I don't even need a liner. Last night my husband and I..well you know and the condom broke. (I haven't used hormonal bc in a long time and I am wanting to get a permanate solution as soon as I get up the courage.) I did use a back up spermicide. Normally I wouldn't even think about the possibility of being pregnant, at this time of the month, but since my periods are kinda out of whack I am always worried. What do you guys think?