Maria Sharapova has vowed to bounce back from a tough two years that left her feeling vulnerable and hurt.

The former world number one returned to the WTA Tour in April following a 15-month doping ban imposed for testing positive for the banned substance meldonium at the 2016 Australian Open.

Sharapova denied knowing meldonium had been added to the World Anti-Doping Agency's list of prohibited substances, and an appeal to the Court of Arbitration for Sport saw her sanction reduced by nine months.

The Stuttgart Open was her first event back and the 30-year-old reached the semi-finals before losing to Kristina Mladenovic.

She struggled in her next tournament in Madrid before suffering a thigh injury in Rome that ruled her out of Wimbledon, having been denied a French Open wildcard.

Sharapova expects to be back in action at the Bank of the West Classic in Stanford next week - where she finished as runner-up in 2010 - and hopes to be winning again soon.

"There was something unique about this particular time off," she wrote in an article for the Player's Tribune. "There is something about a suspension - the judgments, and the scrutiny, and the emotional toll - that is just hard to compare to anything else.

"I'm not oblivious. I'm aware of what many of my peers have said about me, and how critical of me some of them have been in the press. If you're a human being with a normal, beating heart, you know … I don't think that sort of thing will ever fully be possible to ignore.

"And I don't think it will ever not be weird or hurtful to go through."

The world number 173 added: "I feel vulnerable all the time - no different from any other person. And the walls I’ve built around myself … they aren’t nearly as impenetrable as people think. Things still get through, and still make me feel certain ways.

"These last two years have been tougher - so much tougher - than I ever could have anticipated … my passion for the game has never wavered. If anything, it's only grown stronger.

"I'm getting ready for the North American hard-court season now, one of my favourites. I'll play Stanford, then Toronto - and I'm going to give it everything I have. 

"And then I guess we'll see what happens from there. I'm sure I'll win some, and I'll lose some. I'm sure my dozens of critics will show up, and so will my thousands of fans. But ultimately, who knows? 

"When it comes to tennis, good or bad - there's really only one thing that I know for certain. I've missed it."