Keto and weightlifting ?

I do keto and Crossfit, and the benefits are pretty amazing. Depends on what you're into. If you're looking to do straight-up lifting you will want to keep the protein intake moderate to high to ensure your muscles can recover properly and that your body will accumulate lean mass. It's likely that in 6 weeks most of what you lost was water associated with inflammation, so you may want to keep carb intake around the times of your workouts for a while until you get a good sense of how your routine is treating you. Don't fear the number on the scale going back up. One mental pitfall of building muscle is that it weighs more than fat. Use your pant size and photos as more of a guide, and if there is a place that does body fat testing in your area it's worth the nominal investment to monitor that instead of weight because over time the scale will mean far less due to your changing body composition.

"keto" I mean... my computer keeps correcting my spelling

Only do Leto short term. It's very taxing on the body systems and can damage the liver. I've seen somewhere to do a couple months on a couple months off. Below 50 carbs a day puts most people in a ketogenic state. I try to stay around 60-70 to keep my carbs low and lose body fat but high enough that it is able to maintain long term. For the weightlifting on days you lift the rule of thumb is to get 100g of protein that day. Some people believe in doing more, some in doing less. Do your research and try to find what is right for you. Also try to get 5servings of good fat a day. High good fat burns body fat. Some days when my fat servings are low I'll quick force a tsp of coconut oil.