Over fertilized?

So, our tomato plant is taller than I am now. Should I be worried? That is to say, it is taller than I am, even after being pinched back several times + it only has one branch blooming and producing tomatoes. That one branch is going crazy & I think it might break if it doesn't get some support soon. But the whole thing is kind of weird. I wonder if it's not getting enough sunlight or if I gave it too much fertilizer or something...