Could it be real, that smoking makes me feel overcome pollen allergy symptoms for a while? it helps for a brief period.

Odd, but yes: Back in early medical history smoking (of specially compounded mixtures) was used as a treatment for asthma and nasal congestion. I don't know the mechamism, but it was successful for brief periods - enough to please patients. It's not good for the cells and tissue, but it can paradoxically reduce symptoms for awhile. Here's a bit of history: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2844275/