Bong and Rob gave great advice.
If you expect shit you will more than likely direct your awareness to notice potential shitty situations and your intent is subconsciously directed to participate in manifesting shit in your day.
Sometimes we have to eat some shit to get rid of it.
Being that it is your moms b-day you are the one who should eat the shit to get it out of the way, in my opinion anyhow. She is by her attitude manifesting shit for all of you and if you allow it to get on you your day will turn out as predicted.
Eat it up,digest it and let it go... and approach her with a different attitude than she projects.
Be the change you would like to see. Manifest peace and love and it will infect her.
Its her day so go out of your way to make her happy. Draw the shit from her and help her to feel the love that should surround a family, especially on a day like this.
If she says or does something today that looks as though it will turn things for the worse....take charge and redirect it. Tell her you love her and give her a hug. Ask her how you can help to make her happy today.
Focus just on today.
Love works miracles. Love heals wounds and builds bridges.

Have a great day Walka.

peace.