Oh good.
I do think an agent is VALUABLE in this case, I'd just maybe approach a new group.
As old hack said, agents earn their keep. I know people always do the vague "they negotiate a lot of things beyond money" but it's no joke.
-Negotiating the option clause ensures you aren't forced to sit around for months or years, contractually obligated to wait for the first book to publish before you're allowed to sell any more books.
-Negotiating out of print clauses ensures your publisher doesn't keep your rights FOREVER just becuase they stuck an ebook up on amazon, even when it has sold zero copies in 5 years
-Negotiating royalty rates and escalators ensures if your book is a smash hit, you see the maximum $$
-Negotiating rights splits, or negotiating to keep those rights (audio, dramatic, translation) means WORLD DOMINATION! Or maybe just a little extra cash in your pocket
Etc, etc.
These are big clauses, not just silly little boilerplate that ends up being meaningless. They have major impact!