I am on cycle day 48 no period , usually 27-32 i get it, i have a neg hcg blood test ,of 2, but pos very dark pos opk! why?

Delayed vulation: Ovulation can become less frequent as menopause approaches or due to things like thyroid disease, PCOS, stress, diabetes,other illnesses, medications, changes in exercise, diet, or weight. The longer cycle and positive ovulation testing sounds like this is what is going on. See your doctor for a full history and testing to be sure what the cause is in your case. Hope this helps.