If you're willing to play with fire, you have to expect to get burnt at some point.
You've only been with her for 4 weeks? Honestly... There is a HUGE chance that even if she is actually pregnant, it's not yours. If it is yours, you need proof before you tell your parents. Ask her to go to the doctor with you present. Find out for sure if she is actually pregnant. If she is actually pregnant, it still might not be yours. In which case you'll have to wait until the child is born and ask for DNA tests. If she is pregnant and you did have sex with her... you need to tell your parents that there is a possible chance that it's yours. But, you will not know without tests.
If it is your child and you turn your head and disappear... you're a loser. If it is yours you must man up and care for your child. Find a way. Figure it out.
My guess is... She's not pregnant or if she is it isn't yours. She's probably telling you she is so you won't up and leave her after having sex. This has been pulled on me in my younger days.
Bottom line... YOUR LIFE IS NOT OVER.
There are much, much, much worse things that could have happened to you.
Hang in there dude.