I'm only several months older than you, so the advice I'll post is what I tell myself now. It may or may not work for you; I hope it does, even if a little.
- Enjoy the time you can spend with your family (assuming your relationship with them is healthy). They are getting older, and you don't want to regret not spending time with them when you could.
- Emotional self-sufficiency is a must. There will be times when you can't rely on anyone else for emotional support. Learn to go out on your own and to enjoy your own company. That's totally fine. Friends come and go, even close ones; the only absolute constant in your life is yourself. Company definitely helps, but if need be, it's better to learn how to survive on your own now than later.
- A relationship isn't a substitute for the above. Get into a relationship because you want to, not because you feel a need. It won't replace emotional self-sufficiency, nor should it. Your emotional eggs belong in your own basket.
- Don't compare yourself to others; only to your own goals and what you want to achieve. There will always be someone better off or worse off. Don't let that render you discouraged or complacent. No two lives are identical; comparison is pointless unless it motivates you to do better and helps you.
- Take care of your health as much as you can. If the last two years have demonstrated anything, it's that your health-related decisions may have noticeable effects decades later. That body ain't changing; keep it in as good of a shape as you can now.
- Don't let your plans and career isolate you from family and friends. A successful career without a loving, caring social circle is soulless and lonely.
I remind myself of these things frequently nowadays. Some days are harder to stay motivated through than others, but things have been getting better in the last few years--slowly but surely.