Your loan officer most likely has fielded several inquiries from agents in the past. A good loan officer will keep confidential info to themselves, but provide enough relevant nfo to provide assurances to the agents that this contract is solid and will be funded.
If you have made a full loan application, it tells me that you are more serious buyers because you went through the trouble fo submitting the paperwork to the lender (w2, bank statements, etc.), and it tells me that the lender has looked at your entire financial situation and not just at a credit score to qualify you for a loan. I would also ask if the lender anticipates this loan to run into issues.
The loan officer is not supposed to answer questions regarding the source of your downpayment, or any other information as well as the amount you are qualified for unless you gave him permission to do so.
In PA, with the market the way it's been with tightened lending, it's pretty common for a Sellers Agent to contact the loan officer to make sure that the preapproval that the Buyer supplied is a real one - with verified assets, credit that's been checked, income verified, etc.
I wouldn't think your loan officer would have disclosed the maximum that you can afford (you'd have to ask them) - they might have indicated that you can afford the offer you've made or that you're a strong buyer (if you are). But really, you're the one with the money - you decide how much you think a property is worth and how much you'll spend. Just because you qualify for a maximum loan doesn't mean you need to use it all.
Best of Luck,
Talk to your loan officer. It is unlikely the s/he disclosed what you are qualified to borrow. Indded, without talking to you first, the loan officer may not have told the seller's agent anything. The seller's agent should have asked you, through your broker, for permission to talk with your loan officer.