There is no need to panic. The fact that you are sorry about what you did, and the fact that you are seeking forgiveness shows that you have not lost your salvation and are therefore not going to Hell. The only thing you have to do is just say sorry and continue your walk with God. You were in a moment of weakness, and God understands that.
I too renounced my salvation at one point in my life but thank goodness we serve an awesome God who does not hold our moments of weakness against us. I rejected God and walked away from him for 7 years. But even thought I rejected him, he never left me, and spent that entire time trying to win my heart back. Eventually I got back into serving the Lord, and our relationship is great! He never stopped loving me that entire time.
Just know that a person who totally rejects God will become what the Bible calls reprobate. A person who is reprobate knows exactly what they are doing when they reject God and they don't care. If you really renounced your salvation and lost it, you wouldn't be here trying to figure out of you could get forgiveness, and you wouldn't care what God thought about you at that point. We all do dumb things when we get emotional, but God knows our hearts, and he knows whether we mean something or not. Rejecting God is something that is done on a heart level (a conscience decision is made at that point), and not out of our emotions.