Been there.
let's look at some of the reasons of the burnout:
1. You are not a 20 year old anymore.
2. Been there, done that so many times.
3. You got a kid AND (obviously) a partner. This is a major change in your life. Your priorities are changing.
Essentially, what you were doing in the past, is not working and you know deep inside you will not work.
The only thing you can change in this whole equation is YOU.
and so here's what I suggest...
take a break - go away from everything (and I mean everything including your kid) for a week. Suggest going to a small town where there's nothing to do, it's incredibly boring and all you can do is go for long walks. Here's what you should think about:
1. Look at your next 30 years (so long you've coasted along but now you have to plan). Decide what is it that you want to be known for at the end of the 30 years. What is it that you will have wanted to achieve.
2. Make a list of the top 3-4 areas you want to be in. More importantly, make a list of the consequences (both +ve and -ve) if you choose a specific area.
3. Pull together a plan (remember, it will change as you execute it) of how you will get from here to there for each area. That includes the steps you'll take, how will you track it, what issues/risks will come up, your answers to that.
4. Take the top 2 and start doing. At some point, you'll need to dump one area. You can do just one thing in this lifetime...
aaand... if all the above is wrong and it is not a major burnout, then just go for a week's vacation and walk yourself into the ground. Come back completely (physically) exhausted. for me, I need to rinse, repeat every 1/2 year.
Oh yeah finally, Don't take a high end, 5 star resort or something like that. Be frugal. You want the physical discomfort to override the mental pain. You need other things to bother you. For example a friend of mine did a one month travel on less than a $ per DAY across India (and that included staying, food, traveling etc.,)...
Hope this helps.
Best.