The average American doesn't get enough protein as it is, so props to you for getting as much as you do! My personal rule of thumb is to shoot for as much protein as possible. I aim for a minimum of 0.5g of protein per lb of body weight, and I usually get more. The body uses protein in a multitude of ways, like muscle building, tissue re-building (like after an injury), hormones, enzymes, strengthening the immune system, and a bazillion other things, so it's important to get enough.
The body only uses protein as it needs it; if you eat "too much" most of the excess filters out through the kidneys and is excreted as ammonia or urea. A little bit of it also can get converted to blood glucose through a process called gluconeogenesis, but this process is dismally slow and only really plays a significant role if you're eating very low carbs. Unless you already have a kidney disorder, I would say there's no such thing as too much protein. If you do have a kidney disorder then talk to your doc about how much you should get.
To address your second point, like I mentioned above, protein is used for many essential processes within the body, many of which are directly involved in losing weight. If the body doesn't have protein on hand to use for these processes, it will get it by breaking down muscle tissue to amino acids and then shuttle these into whatever processes need them, which is a double whammy because now not only is your body struggling to run some necessary actions, but you're losing muscle too, which means you're burning less fat over time.
Long story short, I think your level of protein intake is great, definitely way better than what most people get (in general, not ppl on this forum!), and it won't get in the way of your weight loss.