These syptoms are due to neuropathy,or compression of the nerve,as the pregnancy
advances and there is water retention in the body there is edema around the nerves,and also as the size of the uterus increases it compresses the nerves at the back causing these symptoms.
One thing is you can start with vitamin E
capsules daily which would help in decreasing your calf cramps.
for the tingling numbness
try sleeping on one of your lateral sides whichwould prevent the compression and also increase he blood flow to baby
Nothing to worry. Take care