How to recover from your horses death?

I feel it s silly to still be upset - I m 22, I only had him 6 months and he was put to sleep 2 months ago. But he was only 15 and I took such good care of him, but in the end nothing could help him - he was an ex race horse and all the racing he did caused a heart murmur. I have a new horse now, who is lovely too, in an equal but different way. But I still cry over Max multiple times a week :( I don t know what to do!