I know that the people who died when I was drinking were never grieved properly by me, as I took the easy way out and drank through the feelings. Maybe you can just accept that you are going to be sad and you are going to think about them, so this is an opportunity for you to grieve as maybe you didn't do when they passed. You could buy them the cards you would have done if they were alive. Write some memories inside them, or some gratitudes for them. Light some candles and put flowers round the room and throw them a party. Go through old family photos if you have some. Eat their favourite foods. Watch their favourite films. Listen to their favourite music. Talk aloud to them. Cry. But try not to make it all about their deaths, and the end of your time together. Allow yourself to grieve with a celebration of their lives.
*Hugs*