It is difficult for me to suggest without knowing your age. However, I will try my best.
Among the blood tests, have you undergone a test on your thyroid profile? Thyroid dysfunction
is one of the common causes of feeling weak in the body.
If it is normal, then check your haemoglobin
. If this is normal too, then there is no major problem in you.
Just follow your routine of eating balanced diet and exercise regularly. Divert your mind into a new hobby.
You will be fine soon.