I have to tell you I am not a vet but just a very experienced person who has cared for a lot of dogs.
As long as she is able to pass stool she should be OK.
Things to watch for to worry about would be suddenly dragging a leg, not being able to lift the tail at all, no more stool being passed, inability to pass urine which could go along with spine problems as if the nerves don't carry the message then the body can't respond.
Here are some groups that might help you afford the vet bills and they range from subsidies or financial aid to credit companies that specialize in medical financing including vet care
American Animal Hospital Association
" Through the AAHA Helping Pets Fund, veterinary care is possible for sick or injured pets even if they have been abandoned or if their owner is experiencing financial hardship."
Angels 4 Animals
"Our services range from financial aid to complete treatment
to those pets and pet owners in need."
A credit card company for health care, including veterinary care.
"With a comprehensive range of plan options, for
treatment or procedure fees from $1 to over $25,000, we offer a plan
and a low monthly payment to fit comfortably into almost every
God's Creatures Ministry
"This fund helps pay for veterinarian bills for those who need help."
"Our efforts focus on serving the elderly, the disabled, and the
"We are dedicated to insure that no
companion animal has to be euthanized simply because their caretaker
is financially challenged."
The Pet Fund
"The Pet Fund is a registered 501(c)3 nonprofit association that
provides financial assistance to owners of domestic animals who need
urgent veterinary care."
United Animal Nations
"The m ission of LifeLine is to help homeless or recently rescued
animals suffering from life-threatening conditions that require
specific and immediate emergency veterinary care. We strive to serve
Good Samaritans and rescue groups who take in sick or injured
animals. In certain cases, LifeLine can also assist senior citizens
and low-income families pay for immediate emergency veterinary care."
They also keep a list of local and national help resources here