Amanda will be okay. She's had a husband who left her, she's raised two children on her own, she's working two jobs to make a living, she's survived several of her gentleman callers, and we have nothing to suggest she won't weather this storm, as well. Amanda is resourceful, judging from her elaborate preparations for Laura's one and only gentleman caller. Amanda is capable, as she is running her household with little help from Tom and no help at all from Laura. Amanda is practical, as she sees the need for Laura to prepare herself for a future alone. (It doesn't work, but it's a decent plan.) In short, nothing so bad happens that I feel Amanda will now be broken or in some other way derailed. I believe she'll be just fine.
As the play suggests, Amanda has always seemed to cope better with setbacks. She was able to raise two children without her husband. So, I suppose she might find a job and work as long as she could. But she is older and is not going to live forever.
My major concern would be for Laura. The imagery and the rest of the play suggests that Laura is a lot like her unicorn. The unicorn's horn, or individuality, was broken during the dance between Laura and Jim. That suggests that for that small moment she was like other girls. But she gives the unicorn to Jim as a "souvenir" indicating he is taking her "normalcy" with him. So the play suggests that she never overcame her shyness and tries to live her life in the small apartment playing with her glass collection. Once she has lost her mother, she might be sent to live in a mental institution, as Tennessee William's own sister was.