Not a good idea to post your contact info on a public forum. I have notified the moderator to remove it.
I don’t know what you mean by “don’t feel right” Please explain more fully.
Yeah, we need more about this, too. Car’s don’t regain speed until you hit the gas. that’s how this works. Do you think the brakes are dragging? Or maybe just one is dragging?
Leave the booster un-hooked. Take a short drive and lock the brakes completely from about 30 mph in a safe area. Get out and look… do you have 4 distinct tire skids? Are they all about the same darkness? Did the car stay straight? Did the fronts lock first? If you can say YES to all 3 questions, concentrate on the master cylinder and booster. If NO, you have a basic problem with the brakes that your current mechanic did not fix. Find a better mechanic.
Hook the vacuum back up. Drive around an vacant area a bit without touching the brakes, or at least as little as possible. Stop and touch each wheel. Are they all warm or hot to the touch? That’s probably a bad master cylinder. If you replace it, get a dual master and have the rear lines broken out. It is much safer. Retest. If the brakes still drag, rebuild the booster again, it was not done correctly before. If one wheel is hotter than the other, the brakes are not adjusted correctly, find a better mechanic.