Sounds about right on all accounts.

Right now, both the Metformin and the drop in carbs you're probably experiencing is going to make you feel like crap for a week or two. Generally speaking, it should level out after that, but you can ease the transition time by ensuring you're drinking enough water and getting plenty of electrolytes (read: salt).

Also, make sure you hit your fat goal. Your body needs dietary fuel from somewhere, and protein is not a fuel source, so when you lower your carbs, you need to make sure your consumption of fat goes up accordingly. The fat will also help ensure you actually absorb and utilize the nutrients you are consuming.

The 3lb/week loss will likely subside after about a month, as dropping carbs very often prompts a drop in water weight and is what accounts for quick, large drops in weight in the first 1-3 weeks. So don't be surprised if it slows down or even comes to a screeching halt around week 4. If your ticker is correct and you need "only" lose 44lb (yeah, I know, 44lb feels like a lot, and may be a pain to lose, but it's a relatively small amount compared to others who can lose large amounts per week for a long period of time, due to having 3-4 times that much weight to lose), then 3lb/week may not be (and probably isn't) sustainable in the long run, and you'll probably want to talk to your doctor about losing more slowly for both short-term sustainability and long-term health and success reasons.