I can't say whether it is Fibro or not but it sounds alot like my story. Mine started in March and not all at once. It started as headaches, then neck and shoulders and back. Then the headaches went away mostly but then it moved into my arms, then my legs, the fatigue hit me last and still not all at once. It was a progression. Now the pain is all over but not all at once...it moves around depending on the day. My fatigue has gotten so bad now though that I drop the kids off at school, come back and lay down, pick them up, come back and lay down. It's ridiculous. My doctor keeps telling me that exercise will help and I try to but it's hard...especially when I feel so weak that I have to rest in between doing the dishes and starting a load of laundry.
By the way, mine started after I was having GI troubles. I had what felt like a bad stomach virus for 2 weeks, then I just caught every illness going around the next 4 weeks....the pain started right after all that.
I hope you find the answers....and I hope your answers aren't worse than the questions. Good Luck to you.