26 weeks and already have cellulite and stretch marks!?

What the heck. Before getting pregnant, I had a little cellulite on my thighs but it was barely noticeable. Now I found I'm getting cellulite on my sides!! and my legs and even my ! I think I saw stretch marks on my and I already have them on my and I only went from a B to a C!! WHY MEE!! I'm only 20 years old and I feel like I will never get my body back. I seriously feel like crying and I HATE all my friends borrowing my jeans i USED to fit in!! This is not fair. I've already gained 20 pounds! Is that bad? I've tried exercising and walking and i get contractions everytime I try to work out! I barely even work up a sweat and I my uterus hardens and it hurts! Also I have HORRIBLE back pain!! My doctor says it's all normal. Is there ANYTHING i can do ANY kind of creams to get rid of cellulite or any special exercises that give you good results? My is so much more jiggly it used to be somewhat firm and now it's like so weird and it wiggles everywhere! I am 5 "8 and before Pregnancy I weighed 145. Now I am up to 167. It's so hard to watch what I eat because I get cravings like a MAD woman!! I really would like some tips to prevent this GELATINOUS body of mine from forming and please anyone does this go away with feeding? Has anyone else had cellulite on their back and sides? It's weird because my sides aren't even that chubby but they have like ripples! And the Back pain!! WHY? Someone tell me this will go away. What can I do? Exercises? ANY TIPS please!!!!!!!!!!! Thank You!!!!