Your sex life, as you have known it up to this point, is essentially over.
That's a scary way to put it =/ It totally depends on your relationship as to how it will change but I can pretty much guarantee it will change, and evolve with your selves and what's going on in your life. Don't read that as sex life over though, you will almost certainly need to put more effort in.
I found out today that im gonna be a father, i'm kind of worried does anyone have any kind of truthful advice?
Hmm truthful advice. Well you'll probably be scared, hopefully excited too, and so will you're lovely lady be. Remember though that she is now going through many changes, especially hormonal ones, but even without the hormones a lot of other things are going to be stressing her out. Communication is an absolute must, and if you need to don't be afraid to seek help (posting here is a good start but maybe not the best way to gather advice and words of wisdom).
This is a time when your own needs need to be put on the back burner, and Hers and the Baby's need to be foremost in your mind and actions. Support love and patience are key. Don't forget though that you are not superhuman either, so you will need to keep something you enjoy as time out, something to keep you sane in the hard times, and there will be hard times.
Having a baby is hard, but it is one of the most wonderful things that ever happens to anybody (unless they REALLY hate kids of course

). Even though it is hard it is so worth it.
Congratulations and good luck! And remember, if you need help ask before it gets too much (even if it's professional help as I've had to do myself in the past).