O'Toole had been released by Burton Albion, where he previously worked with Stags boss Nigel Clough, and was unable to find a club until Stags took him in as a free agent in late October when the 33-year-old admits he was wondering if his career was over.
“I had been trialling a few places and when it doesn't work out you start to think you may have to do something else,” he said.
“You can't trial places from pillar to post and get turned away from places forever.
He added: “You speak to your agent and you have to pester people just to get your foot in the door and I didn't ever think it would be that hard to get a few training sessions here and there.
“I wasn't good enough last season which was probably a big factor in that, but I knew I still had so much to offer. You reassess and re-evaluate what's right.
“That's what kept me going - when you keep getting refused at places and training by yourself in an open park with a few cones and a half-inflated football.
“It does give you a bit of a kick up the backside and all I kept getting told was I was over 30 and people were writing you off.”
He added: “It was quite a tough few months after being released from Burton and everything up in the air. You do start to question how long you will be doing this for.
“I finally got a chance here, everyone has been brilliant and welcoming and I think I have contributed quite well.
“It's all been worth it. I knew I had more to give and I feel pretty good for 33 – better than I thought I would at this age. I've got a good few years left in me and it's going well.”
“With the manager and the way things are going here, all in all it was the best place for me,” he smiled.
“The set-up, everything about the club has been really good.
“I had to seriously consider the other offer I had, but in the end it was too good here to move on. I am delighted it's all done. I enjoy coming in every day.
“I'd like to thank everyone here for getting the deal done as it had been hanging over us a little bit as I was only a short term deal and you're uncertain how long you're going to be there. Plus there was that interest from elsewhere.
“So I am delighted it's all done now and I can concentrate on doing my best for the football club.”
O'Toole might have moved to the other club for more money at 33, but said: “I signed here for footballing reasons and a few personal issues which cemented it as well.
“I knew what I was getting here whereas if you move somewhere else you are moving your family.
“Where I live at the minute I can travel in here which really helps.
“You have to weight up everything which is not easy with so many variables. But I think I have made the right decision and things are going well.”