Hill admitted the home loss had left him with some selection issues and that the set piece and discipline would need to be improved in the West Country.
"That performance has caused me headaches," said Hill. "I would have liked to have seen a good performance against Saracens and then I could have penned in a few people.
"But clearly the way our set piece went is a big concern. With the front five we had we would have expected to dominate the scrum. There is also the discipline to look at.
"It has not made my life very easy because clearly if we go with that team next week, on that performance, we are going to get pumped. We will need to look at selection carefully.
"I'm not saying wholesale changes, but some will need to realise that that is not acceptable and that level of performance is not good enough.
"Clearly changes will have to be made," he added. "There are people who were not here today that can come into the side. Those that played well will know it; the others will know they can't expect to be selected next weekend.
"We all realise we need to produce something special to win next week. Bath have a good defensive record and can threaten you in attack. We have to look at defence and set piece.
"We can win there, but we will be underdogs and need to produce a special display.
"Bath have had a very good win today and that is no mean feat to go to Kingsholm and get a bug win against Gloucester.
"They are hitting some form and have a European quarter final to look forward to too. I'm sure they will look at us and think it is a game they should win.
"We have got an almighty week coming up to really pull ourselves around. We need to be positive and train hard before we have a hell of a game at Bath."