I have read that people are more afraid of aging than dying, but it doesn't have to be a fearful
Depression about aging is a trap. To counteract that, always have at least one goal, preferably several. For instance, make new friends, lose a few pounds, start a journal, write an article or a book, help someone who needs help, walk at least a mile each day, join a gym.
Everyone needs exercise, so choose at least two ways to accomplish that. You will feel much better. Just remember, endorphins are your best friends, and exercise keeps them pumping.
And most of all, find things that make you laugh. There are funny and ironically ridiculous things all around you. Go to the library and deliberately pick out amusing books.
When everything is just too much for you, force yourself to smile. Your own smile will actually make you feel better. Ah, come on. Try it.