What Causes Bloating, Itching And Spotting After A Depo Shot?

I started the depo shot nearly 3 months ago and had no side effects until the last 3-4 weeks. I feel very bloated, am constantly spotting, and have been a little moody. I have been itching over my entire body. I use lotion daily, and drink plenty of water. Could the itching be a side effect of the depo shot? help please!