Depending on how important performance is to you, maybe this is the juncture where you hire a coach?
Here’s my reasoning. You are mid-40s and will turn 50 in a blink of an eye. If self coached training doesn’t work out, you could easily spin your wheels for a few years trying to get back in shape.
Your 2017 was your best year but maybe it could have even been better with a good coach?
I’ve never been coached but I kind of wish I had found better advice 7-8 years ago when I started training again after a long, long layoff. I’m 56 now and had my best numbers last year after several years of spinning my wheels, not improving, and figuring things out by myself. I can’t get those years back now so I kind of wish they had been more productive.