Getting a hold on single mum life

Is mum life is so bloody stressful? Or is it just me.
I'm a full time single mum. My daughters dad has never really been around, so I do absolutely everything on my own, parenting, shopping, school pick ups, paying the bills etc.
Latley I fell so overwhelmed.
I've been studying now for 6 months by distance. I've already fallen behind. I got really sick over winter and was hospitalized for a week. My daughter has also been really unwell.
She has surgery coming up in February to get her adenoids and tonsils removed.
Her birthday is in a week and she is having a party too. Im still trying to get organized for that don't get me started on Christmas next month.
I just feel exhausted. Some days like today I can't even think about studying because I'm so brain dead.
I haven't mentioned having an almost 5 year old with ASD/ADHD is so bloody hard to add on to everything. She does NOT stop ever.
I seem to always be out of the house with appointments or letting my daughter run off some energy, I don't know what I do but I never seem to be at home.

I've always had social anxiety so having a social life is hard for me so I keep to my self which just becomes lonely so it's sort of a lose lose situation there. I have a wedding tomorrow and I feel so anxious. Ive been vomiting all day. It's been a long time since I've seen any one after being so busy with study and my daughters behavior appointments. So thinking about a whole crowd of people is a lot. I see a psychologist once a week which helps but some times I just feel like nothing helps it's all to much that I just want to run away and never come back.

How do you mums handle it all, do you have a planner, or do you have anything that helps with the stress and calms you. Antidepressants have never worked for me I have tired all sorts of them since I was about 14.
Any advice on grabbing a hold on life would be great.