You invented, build, and a product (like a Personal Cooling Unit a devise you wear over your close to keep cool). You have records and receipts of your sales, published pictures, online catalogs, and designs of it open sourced . Can someone put a patent on it and stop you from selling your product?
Simply put, yes.
A little more precisely, there may be existing patents that the product infringes. Either the product as a whole (a personal cooling unit) or parts of the product (like the straps or the cooling mechanism or the power supply) or the way you make the product (for example, a patent on some particular way of assembling the device). The owner of the relevant patent could file a lawsuit and seek to prevent you from selling the product, seek damages from you, or both. Even if no such patent has yet issued, it's possible that someone has applied for a patent already and it will eventually issue.
Yes, if their application pre-dated your public disclosure. Another possibility is the person's product came after yours but the examiner does not find your device or anything else like it. A patent might be granted. In your defense, if sued for infringement, you would have your documentation that the information was public before the other person's filing date. You win in the end but it might be expensive.