Well since you said you aren't taking birth control and arent sexually active the only other thing I can think of would be stress diet change or exercise change. If you havent made any drastic changes like that then I would schedule an appointment with your doctor cause then I have no idea. Sorry if I couldnt help. Let me know how it turns out :)
No, I am not sexually active, still a virgin. Not taking birthcontrol, cause I really don't need it. Any other ideas?
Yeah, just like ku111 said the black blood and unusual/missing periods could be from a couple different things. If you are sexually active and aren't using any birth control or are not using it correctly or it failed then you could be pregnant. I would take a pregnancy test right away just so you can rule that out or start getting help. I know it can be a scary thought but its vital that you take a test especially since you missed your period for two months and then had a very unusual light period. Once you take the test you can go from there on what you'll need to do. If you aren't pregnant then it might've been from stress but I would probably go to the doctor and ask what it could've been from. But since you missed your period for two months and then had a weird light period Im guessing that theres a high chance of pregnancy. Let us know what happens please and if you want you can always message me. Hope this helped :)
Questions, questions, questions!LOL Are you sexually active, are you really active or having more stress than usual? These sure can have an effect on menstrual cycle.