OMG! I am so sorry, I know you had been caring for mom for quite a while...there is nothing anyone can say, I am sure people are saying time heals, she's in a better place and all that crap, but it' all bullshit is bs, it simply fucking sucks, it's a horrible heart ache, a major adjustment.
I lost my mom September of 2016, I had cared for her for over 15 years, I thought I was ready, I thought I knew what heart ache was, I had no idea....I guess I was way to close to my mom, I am glad she is no longer suffering and she prayed for God to take her, but do I ever miss her, she totally kicked ass...no one in this world will ever love you more than your mother.
Anyway you now have two huge holes in your heart :(