Hi Kelly. I can fully understand the way u feel before your monthly cycle because i feel exactly the same way. its terrible. i cry for no reason at all, am jittery, edgy, sad all the time. and this happens to me as much as 7 day before my periods. but as soon as my periods satrt i start to feel better. sometimes i take alprazolam when i cannot bear it. i have spoken to my mother and sister about it and they also have somewhat similar symptoms but much much milder than mine. All that i have been able to find out about it till now is that it is premenstrual syndrome (PMS) and it is common, but nobody seems to have a cure.

this may be depression, but why are you depressed. wats the reason for your depression. life is gods gift not to waste it by making yourself sad. enjoy and even makes others happy. share your depression or any problems with a good friends.

There need not be a reason for depression in the sense that you're making yourself unhappy.  Sometimes it just happens that there is a chemical imbalance in your brain or body that causes it.  At times I get depressed...though I've never had chronic depression nor have I been diagnosed with anything, but usually there is no rational reason as to why I feel or act the way I do, so my conclusion is that there is a chemical cause.