Give it time. Many if not most 1st year clover plots look "meh" at best. It's the 2nd year that they really come on. I'd be surprised if you can't salvage it.
Here's what I'd suggest:
Unless the grass &/or weeds are really taking over and choking out the clover, don't spray cleth or mow this first year. Not doing either reduces stress on the clover. Now, if the weeds or grass are so thick it's choking the clover out, one must react accordingly.
Frost seed more clover into the plot late winter/early spring. Doing that, along with the clover naturally coming on stronger in year two almost always results in a thick stand of clover.
Then in year two you can focus on controlling weeds with a couple mowings and knocking out the grasses with spray. I don't worry much about weeds, unless they are risking choking out the clovers, as many of those weeds are merely extra deer food. Grass is evil, though.
I've had many less than pretty first year clover plantings (starting clover plots from frost seedings are typically the best 1st year clover stands I can produce) and can only think of a couple that were so horrifically bad that starting over was the best move.