I do appreciate your concern on delayed menses since you are used to regular menstruation
From your history, I do not found any cause related to delayed menses. The only noticeable event is history of vaginal infection
treated by some antibiotics course just before menses. Both these things do not result in delay in the menses. However, since no other cause can be pinpointed, you may attribute delay to the infection and/or antibiotics with fingers crossed.
You had some brown spotting
at the time of expected menses. It means that your uterus
was trying to bleed, but some how it was very meagre in amount and hence got accumulated in the uterine cavity
, which later came out as stale blood.
I feel, you may try Tab. Deviry
for five days after which within 4-7 days you should get withdrawal bleeding. If it does not, it is a good idea to report to a Gynaecologist.
If you get withdrawal bleeding, you may observe your menses for next few cycles. If the cycles remain irregular like this, you will have to report to a Gynaecologist.
By the way, you have not mentioned your age. If you are 40+ or in a perimenopausal age, this irregularity can be attributed to perimenopausal changes.
I hope this provides you some guidelines.
Dr. Nishikant Shrotri