Are you sure you're not extremely active, hon? Because I often see you talking about doing an hour + on the Airdyne and then more exercise after that. I'm not saying you're wrong (or that the amount of exercise you do is wrong!), just that biking twenty/thirty miles a day five days a week seems "extremely active" to me. Please forgive me--I don't mean to hurt or upset you, I'm saying this because I genuinely care about you; and I'm also very aware that I don't know how much exercise you're doing/what your typical day is like, this is purely conjecture/guessing in an attempt to help--but I know you've had ED issues, so I wonder if you're not "not seeing" how much exercise you genuinely do. I also wonder if the exercise plus weights/strength training is putting you at a bit of an iron deficiency or other nutrient deficiency, so that's what's going on? I know when I was on 1200 calories/day, I didn't have periods, and I still go through spells where I skip them for months at a time due to low calories or extra exercise. (I am also generally only having them intermittently in the last couple of years, but whether that's due to weight/calories/exercise or to pre- or peri-menopause I'm not sure; I am almost 46, so it's about time for the baby factory to shut down completely. :-( Husband and I haven't been using any kind of birth control for a couple of years now without a pregnancy, so we're pretty sure it's not a possibility anymore and the semi-rare periods I do get are just hormonal [i.e. no egg, just lining].) You are also young, though; were your cycles regular before? How long ago did you start or get out of treatment--maybe gaining weight after so long has thrown your cycle out of whack? Is your mother nearing or in menopause, and how much time do you spend with her? We think the periods I've been getting have a lot to do with our daughters's cycles, since they generally start within a couple of days of each other, and then if I'm going to get one it starts within the next week. Women do synch up if we spend a lot of time together, so I wonder if that could have something to do with it? (I'm not a doctor, of course, so this is, again, just conjecture.) And of course, are you sure you're not pregnant? (Somebody has to ask, right? :-)) No matter what it is, if your doctor isn't worried then you don't need to be. It's not entirely unusual for women to skip periods, even several months in a row. Some women even do it deliberately, by not taking a break from birth control pills, and there are to my knowledge no real health problems with this. After our second was born I had a Mirena coil and, after bleeding solidly for a month or so immediately following implantation (installation?) I didn't have a period for five years. So there generally aren't any real problems with skipping. I do suggest, though, that you visit a gynecologist for a pelvic exam, if you haven't already. I've heard stories about women missing periods due to minor blockages or whatever--I am pretty certain that's not the case here (like, I'm 99% sure it's not), and I definitely don't mean to scare you, but I think it would probably be reassuring for you to just go get an exam and see what the gyn says. If you've never had a pelvic exam, I promise you they're not that bad, and I'm sure your mom or another woman you trust would be happy to go with you if you want. They are a necessary part of being a woman, or they will be when you're a little older, so you might as well get that first time over with now. (I'm pretty vocal about the need for pelvic exams and pap smears; when I was 22/23 I had cervical dysplasia, which is pre-cancerous cells on my cervix. It was caught during a routine pap smear and I was given a LEEP biopsy, which removed all the cells and I haven't had an abnormal pap since. The big thing, though, is that although I had dysplasia I did NOT have HPV, which is a virus that causes many cervical cancers/dysplasias. Now that there's an HPV vaccine I think people assume you can't get cervical cancer if you've been vaccinated/that all cervical cancers come from HPV, and that is NOT the case. So I can be pretty pushy about reminding women to get those smears! Most women your age don't need them if they're not sexually active, but again, I think having an exam would be a good idea for you just to make sure everything is okay and put your mind at ease.) Again, I hope I haven't upset you, and it's not at all my intention to hurt your feelings or patronize you. I assure you, I in no way think of you as "just a kid" who can't figure things out on her own or whatever. You're just the same age as my daughters--you're right in between them, actually--and you remind me of them quite a bit, so... I genuinely apologize if you feel I'm overstepping or talking down to you. I hope you don't feel that way. {{hug}}