"It's very tough (but) I was still able to focus at the last race and I still have that attitude."
The British star, who was placed second at last month's Korean Grand Prix, landed in India for Sunday's Indian Grand Prix only on Wednesday to "maximise" his time with friends and family.
"When those kind of things in your life are good they have a great impact on your life -- and that relationship did. I wouldn't say that I was in great spirits. It's been a tough couple of weeks and I don't think the last race did anything for me," he said.
"It was good to get back on the podium but it's only one race -- it's been a whole year of ups and downs. Hopefully with more races I'll begin to feel a boost," he added.
Hamilton and Pussycat Dolls singer Scherzinger started dating each other in 2007 and their split was announced earlier this month.