Don’t let them freak you out. I had two offers rejected in similarly blunt fashion- both agents came back a week or so later to ask if my offer is still standing. They have to forward any written offer to the seller but of course it’s difficult to verify and enforce.
About the financial Information, I gave mine straight to the agent to show the seller that I could afford the place, or any other place in that price range for that matter. I stuck to my offer and it was eventually accepted.
Don’t let them get under your skin, it’s buyer’s market. That said don’t blame blame me if you don’t get the place ;)