The Dane, who joined the Blues on a two-year contract in the summer, has scored just three league goals in 22 appearances for the Championship club.
However, he told the Birmingham Mail: "It has been tough. It has been hard to just sit there and not get involved. I played the first game and then bang, I was on the bench and it's been stop-start for me ever since.
"I've experienced this situation at other clubs and you have to take it on the chin and keep working hard. I've just got to keep positive and hopefully it will come again for me."
Lovenkrands previously played for Newcastle United.