Even ladies who are menstrating should not have their feet massaged. Hence, pregnant ladies going for massage is a strict NO.
Reason being, the acupressure points connected to all our organs are found at the sole of our feet. Given that you are pregnant, they may apply incorrect pressure ..etc, hence it is just not advisable. In particular, you are in the final semester.
What you can do, use foot cream... and give gentle strokes (certainly Hubby can be put to good use here). While lying down, you may also wish to lift your legs at an angle (not too steep), this helps too.
Hubby can also help to apply the cream onto the calves and giving gentle upward strokes.
Re soaking your feet, personally I wouldn't recommend, especially those with herbs.
This is also the reason why pregnant ladies are not allowed to do hair treatment or colour their hair coz hair follicles and sole of feet are entry points into our inner body.
Just hang on there... soon, you will see a bright chubby happy baby greeting you.
Take good care!!