Raylinds,
Congrats on the nice bike!!
I recently got back on the bike (after 40 years off) and definitely "overtrained" early on...my hindbrain thinking I'm 20, while my lungs, legs and heart were definitely 62 and in horrible shape.
Two things helped me get back into riding shape; 1) a beginners bike training plan that guided slow growth, and a $75 heart rate monitor that showed me workload...showing me when I was overdoing it.
Might not be the thing for you, but that's what got me from; feeling like I was going to stroke out after 5 miles (overdoing it too early), to finishing my 4 times/week 20-30 mile ride feeling great.
The plan, there are plenty of others.
https://www.cyclingweekly.com/fitnes...eginner-153317