Morata started only 24 league games for Chelsea last season after a 58 million pound ($74 million) move from Real Madrid scoring 11 goals as the club finished fifth and missed out on qualifying for the Champions League.
“Last year I was not happy, everything was a disaster. I went out on to the pitch and I didn’t even know where I was,” Morata told a news conference on Tuesday at Spain’s training ground in Madrid.
Morata added that he struggled to deal with the disappointment of being excluded from Spain’s World Cup squad.
“I was ruined, how else could I cope with a summer without going to the World Cup. It was a very tough moment for me, the worst moment of my career and I had a very bad time,” he said.
“It was a complicated moment because I thought I was going to go. Of course I thought about returning to play in Spain or returning to Italy. I left [Real Madrid] so I could go to the World Cup and I didn’t get to go.”
The striker, who has also played for Italian club Juventus is back in the Spain squad for the UEFA Nations League games against England and Croacia and said he has renewed energy and motivation to play for the national team.
“I feel like it’s my first time in the squad. Yesterday I was restless. I arrived an hour and a half early,” he said.
“Sometimes I didn’t appreciate coming here. You don’t realise that you have to perform in every game in order to get called up to the Spain team again until you end up watching the games at home.