New Guinea Pig + Old Guinea Pig = Worried!

Question
Well this isn't really a question but more of a concern.  I have a Guinea Pig, Caramello and hes about 4 months old, i wanted to get him a friend since im not home much and it turned out to be a girl and he is a boy, her name is capacinno, anyway like i introduced them and after 15 mins caramello's going at her like crazy.  And all they do is mate, well he trys she doesnt really want it.  Shes only about 6 or 7 weeks old but if i seperate them they FLIP out, they scream to each other from their cages but lately, i dont know if its normal or not but caramello gets all sickly looking and sort of rocks back and forth and makes what i thought was the mating sound.  but thats all he does when hes with her...its like etetetet..sort of, sorry its hard to describe.  Should i seperate them..or will they bet to heart broken, they've only been together for about a week or so, and they're REALLY noisy at night, normally as soon as i turn the light out caramello shuts up instantly but now they dont shut up at all.  He also doesnt treat me the same either, he usually sqeaked for me as soon as i walked in or out of the room, and i mean scream sometimes too, and now he won't even let me pick him up without running away..he was so tame, and now its all gone i've had him since he was 5 weeks old...i dont know what to do i feel like i've lost my baby and i'm worried their might be something wrong.  Do you think i should get him a guy friend instead of a girl?  Sorry its so long.

Answer
Please separate them ASAP. There is no need to add more cavies to the world as they are already overpopulated and dying in shelters everyday. Especially with your sows age, is is old enough to get pregnant but since she is so young and pregnancy can kill her. If you want them to live together, get your male neutered. Or make a C&C cage and put a divider down the middle so they can still see and hear eachother but not mate. www.cavycages.com
The noise is a mating/dominance noise called "Teeth Chattering"

Also what makes you think your new cavy is a sow? www.cavyspirit.com/sexing