5yr old with various problems

My fiancee's 5 yr. old daughter has been exhibiting various behavioral problems on and off over the last 6 months.

These problems range from crying at everything that happens (she drops a toy on the floor, she cries; her shoe falls off, she cries)... almost anything at any time! She has also been pooping in her pants on and off for the last few months (she doesn't like to go potty, both #1 and #2, and does all she can to avoid it for some reason). She has recently taken to "mouthing off" to both of us when we try to tell her things even just during normal conversations, not just when we correct her for something.

We are at a loss as to why most of these things have been occurring. She's a really great little girl, but lately this behavior is getting worse and more frequent. We have discussed taking her to a doctor, but are some of these behaviors normal, physical behaviors or does she need some sort of psychological help?

Her father is only in her life when he finds it convenient for himself and I'm sure some of this may have something to do with some of these things but what can we do to get her back on track?

[babygirl6152]

whether or not it's normal- it's not excusable- but neither is dad's behavior so as you can see we deal with things being unfair from the time we are born- sounds as if dad is self centered---- he probably want give a hoot that you all are trying to help her behavior but try to get him on the same page

5 years old if she is average intelligence will usually understand "modeling"
The parents- now I am referring to you and mom since you seem to be the one that cares and not her "runaway father" show some silly scenarios with frustrating  reactions, get highly emotional, act out silly - example: Your shoe falls off, you run over and throw it at the wall- play act it all out NOT MAKING FUN OF HER AT ALL- but showing her a learning lesson- this will not be at a time close to when she has shown poor behavior- it will be a time when she has a good receptive attitude- you all will really stay unemotional for the whole thing you all will give her a thrill and she will be giggling her head off- after all that parents will show correct and appropriate responses to life's unfortunate events, dropped icecream, broken toys, lost, balloons, but show her thru your modeling most of all that it's not worth being emotional over- life is great - practicing this mantra with her over and over- "it will be ok" then get on with your happy little life- if she wants to cry let her cry- but you two with your unemotional behavior will be showing her true happiness to problem solving
She's lucky to have you
warm regards-
let me know how it works