I know that please help makes this seem like a terrible thing it's really not.
I am 17 and will be 18 in a few weeks.
Lately I've been thinking about joining the priesthood.
This is strange because it's rarely ever crossed my mind until recently and I've not as religious as I once was. I am still a practicing catholic. I don't pray as often as I used to or even attend mass as often (which I am ashamed of)
I am in a serious relationship that I hope will last for quite a long time (2 years already)
I would like some advice from other people before I ask my priest or even contact someone at a seminary.
This is the first time I've said that I feel like I'm being called.
And about an hour ago I did ask God to help me and lead me.
I would gladly accept my calling if it's true
But I also wish to marry and have children.
I guess being a deacon would be great but I don't think it would satisfy me of my calling we're true. I don't know what to say or to think. Any advice?

I'm not sure what advice you're seeking before you speak to your priest, since I think the priest is likely to give you much better, and more personal, advice than anything you can find on the internet. When you speak to him about this, it's not as though you will make a decision on the spot. Remember that it takes at least a few years of study, prayer, and discernment to determine if you are truly being called to the priesthood.

It's wonderful that you are open to whatever God is calling you to do. I'd suggest more prayer (especially the rosary and some time in Adoration, if possible), and a meeting with your priest or a spiritual director as a first step.

HTH. for you and for all those discerning their vocations!

Entering the priesthood is a real sacrifice, even though you're giving up things you don't actually have (wife, children). You're giving up your dreams and hopes and desires for those things.

http://www.biblegateway.com/passage/?se ... sion=RSVCE

Just remember that you aren't committed the instant you talk to a priest. You aren't even allowed to make a permanent commitment until you've been in seminary for 5-6 years, if that's what happens. So what you're trying to decide now is whether or not there's enough reason for you to ask to be accepted as a seminarian.

This is a very good book on the topic.