You will be much more successful if you learn to take breaks.
We must learn to deal with stress or it will literally kill you. As humans we are only supposed to be incredibly stressed out when we are fighting for our lives. We were not meant to have heart attacks because of non-violent means. Your health is a priority; if your heart can't function in a peak state, neither can your mind.
When a lion is chasing a gazelle, the gazelle's physiology dramatically changes. The gazelle's heart is pumping very fast as it runs as fast as it can to survive. The gazelle's body uses every ounce of energy to focus on surviving. Unfortunately, for many, we are not in peak shape, so we can't deal with the stress.
Other bodily functions temporarily cease working as it tries to outrun the lion. The gazelle's immune system shuts down. The gazelle's reproductive system shuts down. The gazelle actually ages in the process.
Similarly, when we feel too much stress at work and don't treat our systems the way we should, we get sick much easier, we gain weight much faster, our heart can stop working and even our reproductive capacities are adversely impacted.
I have several friends that couldn't seem to conceive. As a couple they became so incredibly stressed out with their perceived conceiving issues that they stopped trying and adopted wonderful children. Shortly after adoption, they had no problems conceiving because they were no longer stressed out; please listen to your body.
1: What to Do the Second You Return from Vacation
One of the best pieces of advice I have received in my life was from a client at Manulife Financial when I worked at Goldman Sachs. She told that the second you return from your vacation, open your calendar and look out 6 months and book your next vacation.
Of course I didn't take this advice as I was in my 20s and felt like I had endless energy. Then I hit a wall and became incredibly unproductive. I had worked too many weekends and too many hours per day. In hindsight all I needed to do was to take a few weekends off and a whole week every 6 months.
When you work too hard without taking breaks you burnout and become incredibly unproductive. If you work for 3 months, for example, around the clock without many breaks, then I am a firm believer that it will take you more than 3 months to "unburnout".
The results can be catastrophic for your career and even your personal life. Pace yourself and take breaks often.
2: Take That Weekly Day of Rest for Your Mind and Body
In several religions, one of the ten rules is to rest on the 7th day. Our ancestors knew about burnout thousands of years ago! You need to take off at least one day per week in order to rest your mind and body.
I absolutely love this wonderful quote from the Dalai Lama when it comes to your health:
"Man...sacrifices his health in order to make money. Then he sacrifices money to recuperate his health. And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."
3: Try 'Screen Free Sundays'
Since my 30s I have not allowed myself to check my work email on Sundays. In fact, I have taught my kids to give me crap if I check any screen on Sunday. They are helping me to not get burned out. Family always comes first, especially on Sundays for me.
Hopefully your partners, supervisors or clients all have children and spend time with their families on the weekend instead of working. If not, you should very politely and politically let them know that your family comes first on weekends (especially Sunday). Heck you come first on Sundays too; relax and recover. You deserve it!
Stress will kill you; don't be the gazelle. See stress as a challenge and not as a threat. Learn to take breaks. Don't walk into the propeller. Hakuna matata!