It is going to leak - a lot - when first launched. One thing many people do is a quick launch like you did to find leaks then pull the boat and put Davis Slick Seam on the outside of the seams that were leaking. The best thing to do is to tent the boat from the waterline down with plastic sheet and put a garden soaker hose under it and wet it down for a couple of days. Then launch. The boat will still leak some, but should swell up more quickly that way. Expect it to leak pretty badly for 4-6 hours and then take up pretty well after that. If you can, put a 110VAC sump pump in the boat to stay ahead of leaks. I normally don't run my boat for about 4-5 days after launch except to go from the launch ramp to the marina dead slow. Until the boat swells up it will be pretty flexible. Swelling stiffens the hull quite a bit.

For my boat I tent it and then dump water under it for 5-6 days before launching.