How do I handle the period in my 40s?

I’m now 41 as of august last year in 2024 and this past year has been a bit rocky shall we say when I get my period once a month. In April I wasn’t supposed to receive it on Sunday but it came Sunday night and made me feel sick on the second day which was Monday which caused me to miss a day of work but otherwise I’m very regular. Fast forward to today my period for May was a day late and even though it’s Monday and this time I have the day off I’m supposed to be on the second day. Why does it start early or late at times? And now I’m on my 5 day schedule what does that mean for the future? I’ll be turning 42 this August. Thanks for any advice.