Not only 2, there is 3.

It is customary for the average Evangelical to think that there are really two systems of theology in Protestantism. They think either you are a Calvinist or an Arminian. This is naive, and really not true at all. There is a theology that is neither Calvinist nor Arminian and in fact older than both - Lutheranism. It is older than both because in the Reformation world, it was the Lutherans who wrote their first Confession, called the Augsburg Confession. In fact Calvin himself signed a variation of the Augsburg Confession also known as the Variata.

Classifying Protestant systematic theologies exclusively into Calvinism vs Arminianism is simplistic and plain wrong.

For a quick view of differences you can study it here

I have a recommendation, if you want to evaluate what you would be between these three, do not start with the Sovereignty of God because that is not how God speaks to us. God speaks to us through the person of His Son. Start with the revelation concerning Jesus Christ and His Cross.

And oh, was Luther a Calvinist? No. Though Luther acknowledged double predestination, he did not go to its logical conclusion in fact he rejected Limited Atonement and Perserverance of the Saints. In this regard, the Lutherans followed Luther contrary to the rumour. You can read an analysis of Bondage of the Will here

Lastly, as one Lutheran blogger said, the beauty of the Lutheran Confessions (BoC) is that you can subscribe to it in good conscience, you do not have to make it appear that it is not saying what it is plainly saying. Unlike those who subscribe to WCF who put their own spin on the sharp edges of that confession, that is why sometimes you would like to ask now will the real Calvinist please stand up!. You do not have to do that in the BoC. You can repeat and assert verbatim what the Bible says even if you sound philosophically inconsistent, you are still Biblically accurate. There is no need to be defensive and do creative (even spectacular) exegesis. It gives you intellectural honesty, it even allows you to be guilt free in your ignorance. You can say - I have no idea, I don't know the answer to that question, I leave that to the wisdom of God. No such pressures at all to be obsessive.