Delayed period and increased stress: What tests should I get to identify the root cause?

Hey there, a virgo here (one of those people still believing in the value of marriage (only it's delayed to some degree) and what comes with it. This isn't meant as passing judgement but to avoid at times hurtful snarky remarks from DR.'s (unbelievable)) That sounds weird to open with it, however it is a vital info). I have been this past few months under a lot of stress at work, including very late remote computer work at night (until 3, even 5am) and dealing with unpleasant people(oh fun:)), my diet was indeed less leaning into the veggies and fruit. What brings me here seeking your advice? My period is sure taking its time (think it's around 54 days since beginning of last menstruation, so it's considered by now missed I guess.)gravitaain between nconstipatiaiton nto normalal to having this one tiimem momentaraty stomach ahache annd diarreah aiwiwith a miild passing fever). Last month regular blood work showed normal iron and HB levels. However, despite being within normal range the ferritin levels were at the minimum level while transferrin on the maximum level within its range. Had some more acne than usual (occasional small pimples on back of hands (a relatively new phenomenon from past years (with the increased stress and worries), ear, chest back face neck. Nothing too severe not a lot either (not as I used to) because I try and treat it keeping it at bay (but a bit more than usual, also not as usual in their location (nonetheless important). My question is what sort of test should I be asking, what sort of blood test to get to the bottom of it, and what should I do also to not augment stress that does not (!) help the situation? Please I'd appreciate your reply