The Eucharist is a mystery. It's not something we do for God, but something God in His grace, kindness and love does for us, where He truly gives us His body and blood for our comfort. You can simply think of it as the Gospel, only in a tangible form.
So, it's ordinary bread and ordinary wine, but by the power of God's Word it's truly Christ's body and blood. We don't speculate on how, but trust in God's command and promise that it does and is exactly what Jesus says it is. Namely, His body for us, and His blood, the new testament (or covenant), which is poured out for many for the forgiveness of sins. In other words, this meal is no ordinary meal. It's supernaturally tied to the cross. In the Lutheran tradition, we call this the Sacramental Union.
The idea that Christ is speaking symbolically does not hold up, for the grammar doesn't allow for it to be symbolism. This was recognised as a great problem to even to the Radical Reformers (Zwingli in particular) who did believe it was symbolic. Basically the sentence: "This is my body" cannot be translated as "This symbolises my body". For this reason, no Bible translation translates it like this. If anyone is interested, I'm happy to elaborate on this.
I used to hold to Memorialism myself, but what made me realise the Eucharist is much more is this:
1. Reflect on what the Bible has to say about sacrificial eating, and consider the trees in Eden, the Passover lamb, and the temple offerings. God often works through physical means.
2. Consider who instituted the Eucharist. It's not a rite made up by the Church, but it was instituted by our Lord Jesus Christ as His last will or testament before He was crucified.
3. Consider when it was instituted: On the Passover, which is fulfilled in Christ, who is the Lamb of God who takes away the sin of the world. So in this meal, we are granted to eat the true Passover Lamb. This is highly significant and a real joy, comfort and privilege! It's not a mere symbol of, but truly is the communion of (or participation in) the body and blood of Christ (1 Corinthians 10:16-17).
4. Consider how central it has been to the Church ever since the beginning. Acts 2 reads: "They continued to hold firmly to the apostles’ teaching and to the fellowship, to the breaking of the bread, and to the prayers." Here we have God's Word and by this loving God, gathering and loving our neighbour, the Eucharist and prayer all listed as central to the Christian faith. This is clearly echoed by the early Church also.
5. Finally, consider the purpose of the Eucharist, starting with that the Bible does not explain it as something we do for God in order to somehow merit His grace. It's not our work but it's God's gift to us.