Endings can often bring about sadness, even when the end is welcome. There is something about "letting go" that makes the heart tender.
It is vitally important to be present while in the midst of everything. Presence breathes life into memory, so that you can reflect on the experience when it ends. If you are not present, then you will be left with fragmented thoughts of what was, which will only heighten the feeling of loss.
Be reminded that the end was once a beginning. When you embarked on this journey it was fresh and new, but everything in life has a cycle and when the course is run, it must inevitably end.
Where one thing ends, something new and different will emerge. Just as a beautiful flower will bud, bloom, and wilt; a new flower will grow and display its beauty. Seek the wonder in what is, remember the brilliance in what was, and embrace the power of what is going to be.