Is the accuracy for the training set?
How many images do you have?
It seems the number of images is quite low, since the accuracy makes such jumps between iterations.
Also, you are fixing dropout to training mode:
x = F.dropout(x, training=True)

During evaluation dropout will still be active.
Change it to:
x = F.dropout(x, training=self.training)

to deactivate it during evaluation.