I Am A 73 Year Old Woman. I Have Been

I am a 73 year old woman. I have been dealing with the shingles for 11 weeks. I also have been on the brand name 5 mg for 35 years. The doctor wanted me to take the original 2 5mg.s mid-day and at dinner. He then got me on Doxepin for bedtime to help me sleep and help with the pain.
I started off with 1/4 teaspoon and move up to 1/2 teaspoon. Is it safe to take the Valium with the Doxepin? I had to get off the Doxepin for one day I was having dizzy spells. It helped wonderfully with the shingles at the beginning. Two days ago I started back on the Doxepin. I took 3/4ths teaspoon, felt ok when I got up , but when I tried to take a shower My legs felt week and I fainted. I took 25mg of Valium spread early morning starting with 5mg at 7:30 AM, 12:00noon PM, at dinner at 7:00 PM, took my two 5mg at bedtime at 12:00AM. All together I took 25mg. I was hoping it would stop the pain in my legs which are coming from Shingles. I can't get any sleep for days. My legs are in horrible pain. Would it be safe for me to take 1/4 to 1/2 teaspoon to help stop my pain in my legs? The doxepin.
Please me! I have been going through so much pain for weeks. The Doxepin helped with that. I am affraid to take it because I am affraid I might overdose.