How do you get the information you lost when you upgrade huawei ascend?

i upgraded my huawei ascend and i lost everything from my apps to my pictures and everything else and i don't know how to get theme back. And yes i logged into my g-mail that your asked to make when you 1st get the phone, and still nothing is working. and i had some very important contact and pictures in there and i really need theme so can you help me please.