Your current code runs into a shape mismatch:
RuntimeError: mat1 and mat2 shapes cannot be multiplied (42x51 and 2142x51)

After fixing it via:
        self.linear_relu_stack = nn.Sequential(
            nn.Linear(51, 51),vvvvv
            ...

you will run into another shape mismatch in the loss calculation:
ValueError: Expected input batch_size (42) to match target batch_size (1).

which is expected, as you are using a fixed batch size of 42 for the model inputs.
Could you describe the data shapes a bit more and how they should be used, please?