Can you get bad batches of meds?

I mean like less effective. I got my valium refilled 2 days ago and it feels like the pills are going straight through me. Even 2 at a time does nothing. I was not this anxious with the last bottle I had. The last bottle worked. So I'm just wondering if I got a bad batch or something. Yesterday I had hardly any caffeine so I thought maybe it was caffeine withdrawels. Today I've had caffeine and its the same thing.

Does anyone know anything about this?

I suspect it could happen. Also, temperature can affect the potency of meds. I used to live in a real hot place and the meds I was on indicated that they should be kept within a certain range of temperatures. I don't think the post offices and post officers had temperature- controlled facilities and vehicles. Some medications are manufactured in countries with very high-temperature climates and I am not sure their warehouses are always temperature-controlled either. Quality control by batch might not be ideal either.