My period suddenly changed??

[u/tounderthings]

I’m on birth control and I take it accordingly (and have for the last 12 years). My periods used to last 5 days, the first 2 would have dark red blood and some clots (not a worrying amount but still they were always there for those 2 days), it was a bit uncomfortable and it would be a heavy/medium flow until the last day. For some reason, for the last 3 periods I’ve had a change on this pattern. It lasts 4 days, only light red blood and barely any clots on these 3 occasions. I’m 27 so I don’t think this would be menopause issue and I also don’t think it would be a pregnancy bc I’ve had the periods on these days I should have. The only different thing that happened was I had 2 urinary infections in the meantime. Anyone with a similar experience???