Coach Plamen Markov and most of the players, including Berbatov, received a barrage of criticism from the local media and fans after poor displays in World Cup qualifiers and the 6-1 defeat against Serbia on Wednesday.
"I fully realise the disappointment and the shame that fans are feeling following the national team players' poor performances recently," the Manchester United striker said in a statement on Thursday.
The defeat against Serbia was preceded by three lucklustre draws in the 2010 World Cup qualifying Group Eight.
However, Berbatov, who suffered a thigh injury in Belgrade and will miss Saturday's Premier League match at Aston Villa and Tuesday's Champions League game at Villarreal, said there is no lack of motivation among his team mates.
"The problems are psychological and are probably caused by the recent negative results and our great desire to qualify for the big championships," he added.
Berbatov, who boasts a remarkable scoring ratio with 41 goals in 66 internationals, has also appealed to the hostile Bulgarian media to give him and the team a break.
"I don't want to mislead anybody that pulling out of crisis will be done with a magic wand and you'll see a new team in the next match. We know a lot of work has to be done," he said.
