Sorry you are having to go through such a sad time with both your parents it must be very difficult 
This is my experience but can be so different for everyone.
My mum died at the beginning of December, she had been poorly in hospital for about 3 months but we had always hoped she would get better, so although we had been told to prepare ourselves, I don't think that anything prepares you for when it actually happens.
Emotionally I was totally distraught to start with yet trying to be strong for my dad and kids. Then it was numbness, disbelief, anger and such sadness. I still find it very raw and can't talk about it really without being upset (apart from with my dad and brother), but I don't cry every day now. Work is a distraction and helps. My family, friends and kids help.
I miss my mum dreadfully and find it overwhelming to think too far into the future without her and the grief can hit any time like a punch in the stomach. I find the littlest thing can set me off, but I suppose it's still very early days.
My work were great and told me to take as much time as I needed (I was off for xmas anyway) so had about 3 weeks, then xmas holidays - I am part time.
Like you, I had lost grandparents which was heartbreaking, but I think this was so much worse for me as was very close to my mum.
Be kind to yourself, there is no timeframe to be set and I think you just need to go with the grief and however you feel. It will be a difficult time, draw strength from family and friends. You may find an inner strength you never knew you had.
Again sorry you have to go through this at all. I wouldn't wish it on anyone 
Take care.