I see that you're still learning the ropes.
Try to incorporate dash-dancing into your routine. It's hard to use at first, but eventually when you combine dash-dancing with empty short hops, pills, wavedashes back/forwards, aerials and jump-cancelled grabs, you can create and exploit a lot more openings.
Were you L-cancelling?
Doc is extremely reliant on grabbing to build up damage, especially in the fastfaller matchup. Grab, up-throw, then you can start chaingrabbing with u-throw or do consecutive jump-cancelled u-smashes. Or you can do a single up-tilt, then go into shffl'd up-airs. Or you can down-throw, then techchase into a f-air or d-smash or grab. Again, grabs are Doc's main source of damage.
I'd advise you against using Doc, not because he's hard to play, but because it's far too easy to develop really awful habits with him. People who pick up Doc tend to overly rely on pills and d-smash and ignore much of his other potential--which is pretty much what I saw in the vid.
Consider using Mario for a while, just to get the basic advanced techniques down. Using Mario--who lacks Doc's KO power and approach options with the pills--basically forces you to figure out how to combo and land grabs, as opposed to relying on pills/d-smash spamming with Doc.
ur doc is real good but it is real average but dont worry practice makes perfect
