Bread or Rock

I baked my bread today. The mixture was well-mixed and it rose and rose. I could smell the yeast - it was gooooddd... Wah, I was so impressed. So I put it in the oven to bake. 45mins later, the bread was ready. I took my knife out to cut the bread.... it was hard as a rock!! Alamak, what went wrong? I was so disappointed.... I told my mom about it and even gave her the b/g story. She said, "yalah, roti dari orang german... dia orang tu kan very kasar, keras... sebab tu roti kau jadi macam tu..." leerrr.....