That’s quite extraordinary, considering that the best U20 400m runner in the current Australian rankings is down with a 47.62.
What competition was that?
Regarding your injury: The adductors also work as hip flexors, and since hip flexion is more active during acceleration, they are more likely to cause problems here. Maybe you can do most of your speed work (i.e. your Tuesday session) with rolling starts or easy, gradual accelerations for a while to help your adductors settle down. I’d definitely drop the tyre drags for now. As a 400m runner your top speed (for speed reserve) and speed endurance are much more important than acceleration anyway. Are you taking ibuprofen or some other NSAID (orally and/or topically)?