Frankie Dettori fears he may never salvage reputation when Italian returns from six-month ban I'm ashamed and embarrassed. It was one night of madness with friends. I dropped my guard when I was at my weakest. I was in a dark place. I was very low, my job was going down the drain. One of the biggest names in world racing, Dettori tested positive for a banned substance, believed to be cocaine, at a meeting at Longchamp in Paris last September. Jurisdictions worldwide, such as the British Horseracing Authority, are expected to reciprocate the terms and Dettori's next important date is when he will be summoned to the headquarters of France Galop to be retested towards the end of April. Dettori's suspension was backdated as he had already been prevented from riding in France since November 20 when an independent medical commission spoke to him via a conference call and passed the file on to a disciplinary panel of the stewards at France Galop. The three-times British champion jockey said the indiscretion came as he feared for his future after his 18-year association with powerful owners Godolphin came to an end in October. Dettori, who was cautioned by police for possession of cocaine in 1993, said: "The last three or four months have been very strange. It's been frustration, unhappy times. I've been in a bad place. It got to the stage where I wasn't flavour of the month any more and the love was gone. Watching someone else riding my horses while I was sat in the weighing room wasn't a thing thing that I was used to. I wanted to be in the number-one car, not the second driver. Inside myself I wasn't happy, which is why I let my guard down - I made a mistake. Dettori played down any suggestion the ban could signal the end of his career. He plans to operate as a freelance in 2013. My ambition for the next five years is to get my career back on track and start doing good again. I feel like I have a point to prove now. I still need to come back to show I'm still as good as I was. I want to redeem my name.