Hi!
The answer by @spacemeerkat seems to be the correct way to go (see PyTorch: Saving and Loading Models 4)
from your_model import model  # Replace your_model with the name of your model class
m = model()  # Create a new model
state = torch.load(saved.pt)  # Load the whole dictionary, as that's what you have saved
m.load_state_dict(state[state_dict]) 
# There is no need for m.train() if you want to continue with training

P.S.
You are always saving the state in the same file. This leads to only the newest model state to be saved.