feel so worthless

I'm 30 years old. I got divorced and just moved back with my parents. I have been off work for a year and a half (since I got preg), I had an amazing job but had to move to another country with my ex husband. I'm now looking for work again but I feel worthless. I hate living with my parents I feel like a kid but I literally can't afford moving out now. I have money saved for a downpayment on a house but I'm around 10k short so I can't use this money.
My mom gets involved too much in my business and my sons like why are u still breastfeeding him (he's 9 months), why doesn't he take pacifier, why r u feeding him this, why are u spending so much time with him etc. 
I take a course on Saturdays so I'm gone for about 6 hours. She watches him while I'm gone and makes it seem like she's doing me the biggest favour in the world. Ido clean the house and cook 3 times a week.
My sister has two kids and mom happily let's them sleepover at least 3 times a week. When my mom says no to her she simply talks back. My sis is divorced too.
She always looks up to my bro whose a professor and loves my 20 year old brother to death.. I just feel so naive, I never talk back and this is why she's stepping all over me. 
I feel so sad right now.. so worthless.. hopeless.. I was hugging my son and crying, I don't see any light at the end of the tunnel..