So, I'm on the depo shot and it's almost due for my second round. I've heard that there can be spottig during the first 3 months of your first shot. However, I am sexually active and we don't use protection. Also this past week I have been feeling sick, I have weird mood changes and I've been hungry, almost having weird cravings. Is there a possiblity that I may be pregnant? Even though the shot is 99% effective?