Dear user, It is nice to know that you are trying very hard to lose weight. Muscle cramps
, stiffening of muscles are very common occurrence during workout particularly of calf muscles and this may be reason for the bump in the calf. Probably you are trying a bit too hard which is responsible for your symptoms such as numbness
of foot. I would suggest you to stop at the moment, give rest to your body, and see a doctor if symptoms don't subside. Once symptom free, restart at a slow pace, do warm-ups, gradually increase the duration of exercise, maintain proper fluid and electrolyte intake to avoid muscle cramps, preferably work out with a trainer.