Crazy hormones ?

Im currently BF my little boy and while  there are plenty of pros , there are also a few cons . Mainly an imbalance in hormones resulting in irregular periods . I got my first period in January , and all the following cycles seemed to be six weeks apart , my last period was very odd and was mainly spotting . Not uncommon while breast feeding . We'll I'm supposed to be in my fertile window this week but a little over a week and a half ago I had fertile cm . I haven't been using opks , checking temps ect ..but I've been getting head aches , cramps , and my back has been killing me and also thick lotiony cm , idk if I should assume this is just PMS or if I should test ?