Quite understand the concept of not enough time to sleep.
if you can, try and take 15 minute break over your lunch period and lie down. Having a power nap is not easy for many but it you concentrate of relaxing each part of you from your toes up, this helps to go into relax mood. When a thought, any thought comes into your mind, acknowledge it and then throw it away..... attempt to have at least 5-8 minutes of relaxation that may fall into a light sleep..... set your phone alarm to avoid having an hour..

If, not then catch up on the weekend...
other than the above, no other solutions I am afraid.