I don't get headaches. Instead, my language exchange partners get them, when I butcher their language...lol!

Headaches are a sign that you need to relax.  There is no way you'll make progress.

I haven't tried aspirins for wine, but a long rest does the trick.

I think you are just putting unnecessary pressure on yourself :)

I measure progress in quite a simple way, I just look at how many books I have read, and how many TV series I have watched.

It can feel like you are not making progress at times, but that is exactly the process! You are making progress, its just its not as noticeable as when you first started learning, so keep at it! :)

I sometimes get tired when I am speaking in a foreign language, but that is completely normal, so I dont let it bother me. Whatever you do with the language, just make sure you enjoy it!