I have been having same symptoms. Within a week I gained 10 pounds, and my stomach was so bloated I looked pregnant. Even my 9 year old son noticed it. I am not pregnant. And I have been having severe back pain. I have had bloodwork, my thyroid is fine. I had a CT scan and everything is fine. My weight has been stable for years. I had to go out and buy different clothes. I am 46 and the only other thing I can think of is that may be hormone related. I know this sudden weight gain is not normal. My doctor doesn't seem concerned and I am having a hard time getting him to listen to me. One week my weight was the same, the following week i couldn't fit into my pants. I don't know what else to do. It is really depressing.