Looks like there is an issue with your nutrition. Don't do drastic diet changes for fast wt gain/wt loss/muscle build. Get your Hemoglobin checked as well. Do not consume capsules/powders etc for the same without having knowledge about it. Consume more fresh fruits and vegetables as per the season. Keep nimbu pani with you during your workout. Don't dehydrate. Regarding the bone pains/weakness, it can be calcium deficiency. You can take weekly once vit D3/calcium tablets for bone strength too.

Please share more details on your health and food you are consuming. Based on that we will figure put the causative and i will guide you further. We are what we eat