Taking time for myself ?

Has anyone ever disappeared for a day or two without warning or notice? I have a daughter and I plan on taking her with me to a hotel or something (I love her so much) but I'm feeling really depressed, sad, extremely sensitive and taken for granted.
I am seeing someone who has me feeling a bit insecure and I think it's just because I'm getting attached. I'm used to getting hurt and was single 2 years before talking to him. Long story short I have some doubts and some trust issues going on in my head.
I am also dealing with an angry negative alcoholic mother who just puts me in a bad mood almost daily, all while going to school and working. 
I just find myself crying often when I'm alone and that's not like me at all. I feel like it might be selfish of me to just get up and leave, take a breather and think without letting anyone know and turning my phone off. Like... I don't want to talk, I just want silence, peace and to get myself together mentally again because I'm losing my grip. Has anyone ever done this? Did you feel better?