First time Guinea Pig owner, need help badly.

I recently purchased a female guinea pig from a petshop in which the cashier/owner was blatantly irresponsible. He didn't even know the sex of the guinea pig, nor did they have the sex of the guinea pig written anywhere. I took the cavy home, and I did a search and found my way here. I determined from the pictures that the cavy was in fact a female. But her size is what confused me. She looks to be about 8 - 13 months old. Her sides are bulging, and when I pet the sides of her stomach...she makes that "uncomfortable" anxiety pur/sound. I decided I wasn't going to pick her up until I found out whether she was pregnant or not. Are there any signs I can look for? I'm sure you get these questions alot, so sorry for being redundant.

Thanks for the answers. Wait, thats right....NO ONE GAVE ME ONE.

She had 2 babies, a boy and a girl.

Thanks again for no help.

I'm sorry but was also a new g. pig owner who bought a girl g. pig pregnant and she just had 3 babies. two boys (i think) and one girl (i think), they are actually 7 days old. I went on to cavy lynx and the people there helped me. I warned you now be very careful who you talk to. Swannie and %%WORD40%‘1kids are really very helpful. Watch the others and make sure you speak to swannie, she good. I'm been following my niece and my instinct, my babies weighed 4oz each and now weigh 7oz each. I'm enjoying them but theres a lot of work to do. Let me know how old they are and what they weigh. Maybe we can help each other out.