If you are only taking in 500 cals a day, its possible your menstrual cycle will stop b/c you are starving yourself.
I have had an experience before where I tooks a home test and it was a false positive, and that cause a LOT of problems, so I will probably just wait for a blood test, I have completley lost my faith in home tests. I am having such a mental battle here because I KNOW I need to get to a doctor asap, for the health of my (possible) baby, and that is driving me crazy because I want to go like NOW, but my only transprotation is my fiancee, and I don't want to tell him until I'm SURE, because I do NOT Want to go through another senario like last time...it was messy. Ugh, I dont even know what to SAY "hey baby take me to the doctor i think we're having a child"! I mean, it's not like he'd be pissed or anything, he would be happy, but then if it turns out I'm not he'll be all depressed like last time, I can't watch that again...I guess I should just get a home test. At least I probably haven't hurt it already, thats a HUGE releif, thanks.
Okay, firstly, you need to take a test, of course everyone will say that. Secondly, if you are pregnant, the baby will take what it needs from you first.. Before those nutrients get to you. I know that almost doesn't make sense, but in other words, your body will provide for the fetus before you. Also, if you were pregnant the fetus at this point is actually not even a fetus yet, it is an embryo and it is likely in the phase of cell-division, so it's highly unlikely you caused any damage with your diet. A sudden change in diet or exersize, however, can alter your menstrual cycle. A baby is able to strive in some of the most deprived women's bodies, believe it or not. The human body is an amazing thing. Now if the conditions were bad enough, the woman may eventually miscarry.. But I can tell you that while I was pregnant I had a poor diet, and a stretch of almost 2 weeks where I was SOO stressed out I could hardly force myself to eat ANYthing.. And as you can see, my baby is just as fine and healthy as can be.
So if you have a doctor, request a blood or urine test. Or simply go buy a test from the dollar store. Considering you are so late on your period, a positive should show by now.
Best of luck!