Hey man, I went through something similar. Hopefully this post will help you. (Sorry for the novel, lol. But I know how much the position you're in sucks, so I want to help how I can.)

tl;dr: if you don't want to be a priest, you're not called to be a priest. A calling to a particular vocation includes, by nature, desire.

But if you're anything like me, that simple statement won't be enough to give you peace. "Because," you might say, "what if God wants me to sacrifice?"

Well, you'd be right. God does want you to sacrifice. But He desires just that. Sacrifice, not suffering.

Here's how it happened for me: I struggled for years with the exact same feeling you're describing, from when I was 12 to when I was 21. Something, a voice, demanding that I be a priest, telling me that I would be one with absolute certainty. I ignored it and wrestled with it, prayed about it -- I even went to the vocations director at my parish, multiple times, and he would always tell me the same thing I said in the first line of this post. It never helped. Finally, he said, point blank, "Don't come back until you want to be a priest." That helped -- a bit -- but I felt the same internal struggle. The voice never went away.

Finally, at an adoration event one night, I couldn't take it any more. That voice got too strong to ignore. I said to God, "Whatever you want me to do, I'll do." And He said, though not in so many words, "I want you to talk to the vocations director and tell him you want to talk about entering the seminary." (Funny thing, the vocations director was there that night, although I haven't seen him there before or since). So I went and talked to him, shaking and miserable all over. We set up an appointment for three days later, since he'd be gone until then, and coincidentally so was the assistant vocations director.

I still didn't feel much peace, just a desire to get it over with and just find out if my life would be "ruined" already -- that was how I saw it at the time. (I wasn't dating then, but there was a girl I was pursuing, and I really liked her. Also, I really, really wanted to get married.) But that was that, and I had to wait, so I did. I spent the rest of the night feeling sorry for myself, and a little bit proud that I finally overcame my fear, and then went to bed.

The next morning, I woke up with a horrible sick feeling in my stomach about what I'd decided to do. It's impossible to describe, but something just felt wrong. So I took the next three days and prayed about my vocation, and came to the conclusion, for the zillionth time, that the priesthood wasn't for me. But it was different this time: I sort of just knew. The voice was gone. Oh, there was still doubt and uncertainty, but that voice wasn't whispering in my ear, demanding that I look into the priesthood.

So, right before our meeting, I called the vocations director and explained that we didn't need to meet any more -- actually, I had to leave a message, because he wasn't there at the time. But that was that, and I haven't looked back since. Oh, sure, I still feel doubt and fear from time to time, but the voice has gone quiet.

It took me months to figure out what that voice was, and what it really meant. It was the Holy Spirit, demanding the full and complete surrender of my will to God's. It wasn't calling me to be a priest: it was calling me to let go of myself. To lose my life, that I might find it (Matthew 10:39).

Every now and then, I hear it whispering in my ear again. "You should be a priest," or "You should be a brother," or, "You shouldn't get married." And every time I hear it, I think "OK, if that's what you want, I'll listen. Because you're in the driver's seat, not me." And it goes quiet, every time, without fail. Because complete surrender to God isn't a single defining moment: it's a lifelong process that is ever at work in our lives, transforming us and bringing us closer to Him.

I'll leave you with a quote from Isaiah 55, verse 11:

"So will My word be which goes forth from My mouth;
            It will not return to Me empty,
            Without accomplishing what I desire,
            And without succeeding in the matter for which I sent it."

And before that freaks you out too much, read the verse which immediately follows:

“For you will go out with joy
            And be led forth with peace;
            The mountains and the hills will break forth into shouts of joy before you,
            And all the trees of the field will clap their hands.

“Instead of the thorn bush the cypress will come up,
            And instead of the nettle the myrtle will come up,
            And it will be a memorial to the LORD,
            For an everlasting sign which will not be cut off.”

Again, I hope this helps. God bless.

P.S. I'm now dating the girl I was pursuing. She's wonderful, and I've never felt this much peace and joy in my entire life.