Periods flow decreasing over time. TMI !!!

So I am 28 and have been trying for a year. Sadly there have not been any bfp here. However, from 23-27 I had the IUD (non hormonal). My periods have always been very heavy and painful. Usually pins before period. I usually took painkillers, then for the first couple of days I’d be really heavy and then It would lighten up. I would bleed for a total of 5-7 days. However, within the last year I have notice my periods being very light. Sometimes I could wear just a panty liners and it’ll last for 3-4 days. I get the occasional cramp before but nothing unbearable. I am worried that there is something seriously wrong here. I don’t even know where to start. I have had three scans within the last year in case I had any cysts but nothing. Reaching out for people who have had similar issue.