Let me just start off with a word of comfort and firm answer to this, and that is, as you believe in the person and works of our Lord Jesus Christ, and as you are baptised into the name of the Father, the Son, and the Holy Spirit, you are saved. You will go to heaven. Your salvation is secure in the promise of God. Mark 16:16 reads: "Whoever believes and is baptized will be saved, but whoever does not believe will be condemned.", and this promise of salvation is absolutely for you.
There is nothing you need to do to sustain or supplement your salvation. The Holy Spirit has made you a new creation in Christ, so that you can freely do good works. We do not do good works to merit or sustain salvation, but upon being saved, we are granted to do good works, which are the fruit of the Holy Spirit in us, sanctifying us.
Furthermore, on a very practical level, if you ever find yourself worrying about your salvation, you can take that as a sign of comfort in and of itself, as Godless people do not worry about their salvation. If they did, they would repent and believe.
Now to what the Roman Catholic Church teaches on the subject, and the (orthodox) Lutheran response:
According to the Roman Canon of Trent, you and me both, fall outside the Roman Church. But this is no reason to worry or to be alarmed, for Trent is not a good and Biblically sound decree; it is fundamentally anti-Gospel, and so it should be rightly rejected. Trent explicitly denies justification by faith alone, which is very sad, for the article of justification is the most central doctrine to all of Christianity. Because of this, not only Lutherans, but also Anglicans, Calvinistic Reformed, Arminian Reformed, and all the Reformed daughter bodies, rightly reject the Roman confession of Trent. The Roman Catholic Church has many good qualities, but Trent is one of their worst.
In Vatican II, however, the Roman position is somewhat softened, and with the recent Joint Declaration on the Doctrine of Justification, they do officially hold that Trent does not apply to those Protestant bodies who subscribe to this document. This is, to put it mildly, very arbitrary, and not a particularly honest union.
So, let me sum up how absurd this position is - According to the Roman Catholic Church, if you're in the ELCA (who do subscribe to the Joint Declaration on the Doctrine of Justification), then you're "in". If you're in the LCMS, you're "out". And if you belong to a different religion altogether, such as Hinduism or Shintoism, and have never heard of Christ, but live a very pious life, you might also be "in". Needless to say, this whole idea is not true and not good. We can confidently reject this position and cling to our hope in Jesus Christ, who is our Redeemer.
As orthodox Lutherans, which includes the LCMS, we consider Roman Catholics to be our Christian brothers and sisters, and we do believe that the Roman Catholic Church has the Gospel, only obscured. But we firmly and rightly reject the Roman teachings as expressed in Trent.
