Tharanga, 26, who is back in the team for the first of five One-day matches against the visiting Australians, missed a tour of England [ Images ] because of the ban.
He pleaded guilty after claiming the banned steroid was in a herbal remedy.
And he was back playing cricket on August 9 after the International Cricket Council [ Images ] accepted he had not taken the remedy with the aim of enhancing his performance.
"It was one of the most difficult situations I have experienced. The ban affected me psychologically and that was one of the toughest periods in my life," Tharanga said before Wednesday's game at the Pallekele Stadium in Kandy, reports AFP.
"Fortunately that is over now and I am looking forward to the future."
"I was shocked when I got to know that I had failed a drug test. I just couldn't understand what had happened," said Tharanga, who scored 395 runs during the World Cup at an average of over 55.
"Playing in England is what every player wants to do. It's a unique challenge to play and succeed in England... It was disappointing to miss out on this occasion.
"Everything is over now and the captain and the selectors have recalled me as soon as the ban is over. I am looking forward to do well in this series."
The One-day series will be followed by three Test matches, also against Australia [ Images ].