I know all about midlife crisis. It depends on what interests you, i walk my dog and do alot of things outdoors, i try to make new online friends that share the same unrest and boredom that i do. Hang on there
I slowly got into scrapbooking, but I never got around to actually printing my photos, so instead I started making cards. I'd get a piece of card stock, slap some stickers on there and give it to my neice or nephews. Now, after 5 years of doing it my skills are awesome and I'm selling them!!! I started slow, using a yellow button for the Center of a flower... Before you know it you'll be addicted!
I'm not in the mid-life crisis age but I am a stay at home Mom and that has it's own crisis. You lose yourself in the day to day. I enjoy designing and making jewelry. I dont know what your interest are but that might be something you'd enjoy.Doing crafts are also fun. Try your hand at painting and drawing. You might take a class on something you've always been interested in too.You might discover talents you never knew you had due to not having time for yourself.