You are doing a binary classification so the output of the module will give you a 2d output where first dim is batch size and the second dim is the output size.  So, you need to squeeze the output or unsqueeze the real labels.
I cannot say anything for sure because I cannot see all the codes but as far as I understand you are using a data loader with batch_size of 32. If you have less than batch size, data loader will use number of example. If you have more example than batch size you will get output for each batch.