You might have endocrine problems - sweating and nails clearly point to thyroid problem...Thyroid gland (and parathyroid glands that are inside thyroid) regulate level of calcium, if there is no calcium, nails become soft, not to mention sweating, nervoussness, maybe irregular heart beating.
Check your ALL hormonal levels: thyroid, parathyroid, sex hormones, adrenal, pituitary gland hormones...
After that you will know what is wrong.
There are many natural ways that can heal the imbalance.
I wish you a lot of luck.