Should I be concerned about menstruation changes?

I have a fairly regular cycle with 7days of menstruating. 1 light/medium day followed by 2 heavy days requiring changes every hr, even needing to get up through the night and then 2 medium days and a light day and a spotting day. This is my cycle on & off birth control, which I haven't been on in 6-7yrs, it is pretty much clock work.
I had my last regular cycle Jan 2, 07.
I had 40 days go by (usually 29-30) then only 2 days of menstruation which were light to medium.
Then 29 days and again with the 2 days of menstruation with some spotting.
During the 40 days with nothing I did a home pregnancy test that came up negative.
Should I be concerned about these changes on my flow? Is it normal to have such changes? I hate gyn apts & don't want to make one if I don't need to. Like any of us do.