Hi, I only had one depo shot in Oct, I was due for another Jan 12th , but did not get the injection. I have recently for the last couple of days had some mild cramping in my lower pelvic region, similar to menstrual cramps, also noticed today very tender nipples , as well as urinating frequently for a while now, some nausea, gas, and constipation. Could I be pregnant even though I don't even know I'd I ovulated?