Speaking to Ian Ladyman of the Daily Mail, Lingard explained he's had to care for his younger brother and sister, and concern for his mother has impacted his demeanour and form on the pitch.
The England international said he decided to speak out about his issues after Ole Gunnar Solskjaer challenged him over his declining performances.
"I wasn't performing, and he was on me all the time. He wanted more from me," Lingard said. "So I felt it was best to get everything off my chest and tell him why my head wasn't right. So I knocked on his door."
Lingard explained he's very close to his family, and in addition to his mother's illness, his grandfather has been diagnosed with prostate cancer.
The midfielder is now caring for his siblings, aged 14 and 11, along with his own one-year-old daughter:
"I have been down and glum; just worrying. I felt like everybody just passed all the stuff to me and it weighed on my shoulders. It was like, 'Here you go Jesse, you deal with this on your own.'
"My mum has had some things for years but never really got help. Now she is. So I have been taking care of my brother and sister. They are with me. It has been tough to see my loved ones struggling and then I have to come to work and try to do my job."
Lingard added he found it difficult to talk about the issues he faced and decided to deal with his emotions on his own. However, spiralling form saw him lose his place with United and England, prompting him to open up.
"I've had to mature and wise up," Lingard said. "Sometimes when your worries are so deep you can't function properly. Now it's about getting back to my best, and I feel I can do that."
The player said his conversation with Solskjaer boosted his confidence and helped him focus on his game once again.
Lingard also addressed his use of social media and admitted he has made errors. Solskjaer was angered by a video posted by the Warrington-born player last summer, and Lingard said the Norwegian told him he was on his "last chance" at Old Trafford.
Lingard has started just six Premier League games this term and has been used as a substitute seven times by United.
The 26-year-old has been a useful option for the Red Devils over the years, and his experience is vital to Solskjaer, with United opting to promote youth.
Lingard recently captained United for the first time, and if he can continue to improve his form, he could fight his way back to a regular starting role for club and country.