Marion, the "flood of referrals" from your first gig is not surprising. (These places are, as the A. D.s often say, "always looking for new entertainers." and most will try you without an audition--especially if you're recommended by a prior client.)But referrals are like seedlings. If you don't tend and cultivate them, they tend to dry up. By all means, keep the clients and prospective clients posted as to your interest and availability.
And if you go the agent route, tell us how that works out. I'm interested in hearing about your adventures in this kind of venue anyway.
Genie