Hey Evelyn, gosh a Dr. on the forum, welcome but at the same time sorry you are here!
Yes, you will see an increase in drowsiness .... this wears off a little but never completely goes away ... best to take it earlier in the evening if need be to decrease lethargy in the morning (I think I settled on 9pm). 20mg remains a pretty low dose though, as you know. I took 20mg for a while but recently quit the drug as was doing better. However, I'm not fully recovered and am considering returning to the drug. Depressed patients used to take 150mg of the drug in days gone by! My psychotherapist told me I was taking a 'homeopathic' dose, lol!
I found on 20mg I was able to work and get on with life. After many months at 20mg I found the worst side effect was the minor constipation, everything else was tolerable. Even the dry mouth disappeared.