Plumber's advice

Hello to any people with plumbing experience and anyone willing to have a guess.
For the past month or so my shower has 'gurgled' towards the end and after the shower has finished. Lately, even after brushing teeth/washing hands, the hand basin in the same room also has a (smaller, higher-pitched and less long) gurgle.
A few days ago, by the time the shower was finished water wasn't draining immediately, i.e. one cm or 2 of water had accumulated. That drained away after 5 or 10 seconds, with the same gurgling/burping water sound.
I assumed hair had clogged up the pipe, so yesterday and today I put some drain-cleaner stuff down. Still get the gurgling sounds, but water does seem to have stopped accumulating by the end of the shower.
Do you think I'm on the right track, i.e. it's just hair/whatever, and I should keep doing the drain-cleaner routine for a couple of more days? Or, is it time to call in a plumber?
Hmmm....
For the past month or so my shower has 'gurgled' towards the end and after the shower has finished. Lately, even after brushing teeth/washing hands, the hand basin in the same room also has a (smaller, higher-pitched and less long) gurgle.
A few days ago, by the time the shower was finished water wasn't draining immediately, i.e. one cm or 2 of water had accumulated. That drained away after 5 or 10 seconds, with the same gurgling/burping water sound.
I assumed hair had clogged up the pipe, so yesterday and today I put some drain-cleaner stuff down. Still get the gurgling sounds, but water does seem to have stopped accumulating by the end of the shower.
Do you think I'm on the right track, i.e. it's just hair/whatever, and I should keep doing the drain-cleaner routine for a couple of more days? Or, is it time to call in a plumber?
Hmmm....