'Gilligan's Island' Star Dawn Wells Suffering Financially After Surgeries

"Gilligan's Island" star Dawn Wells is severely down on her luck -- nearly $200k in the red -- and she's seeking financial aid from Gilligan fans ... TMZ has learned.

Dawn famously played Mary Ann Summers on the iconic TV sitcom, but according to a friend who launched a GoFundMe she's desperately in need of money so she can move into an assisted care facility.

The friend tells TMZ ... Dawn broke her knee this year, and was already recovering from a major surgery where she suffered complications. According to the fundraising page, she's been struggling since losing almost everything during 2008's banking crash.

The GoFundMe page says Dawn, who's now 79, needs to be moved to a smaller assisted living home that caters specifically to people in the film/TV industry, but the facility won't accept her because she's $180k in debt. The friend tells us Dawn has no family and has already lost her home.