SHOULD I TEST? PLEASE HELP!

Margarita

my period usually is 7 days but since i got off nexplanon on july 17 my 2 periods has been just 4 days (before it was 5-7 days ) on July 30 i got my period for 4 days and August 29 i got my period for 4 days which is today im done . Could it be that my period is now short? also should i start ovulation testing now that im done my period?