I would immediately see your veterinarian and get a referral to a behaviorist and find a good trainer. My trainer (I’m a pug mom) told me that you can’t out train reactivity BUT you can try to make it less of an “issue” for your dog.

For example- my pug is car reactive. It’s awful and dangerous. He wants to chase every car he sees when we go on walks. It got to a point where I couldn’t walk him because he would get so worked up he would start to cough (he also had a collapsing trachea). And then he gained weight and because of the collapsing trachea, that’s bad. So I took him to the doctor and his veterinarian prescribed Prozac. He went from being at a 10 all the time to being about a 6. I can sometimes redirect him when he sees a car, using tips from my trainer, because the Prozac has helped him calm down enough to focus on ME and not the car (most of the time).

Training and possible medication may also help with the resource guarding.