Happiness in life isn’t a constant state of being. It’s completely normal for it to rise and fall as time goes by. The year you fall in love might represent the peak of happiness; the year you lose a loved one is likely a low point.

We joke that the years before the reality of work and bills are the height of happiness. Remember when getting mail was fun and not a reminder to pay your Internet bill? And having a job sounded glamorous and didn’t involve long hours at the office? According to a new study from the National Bureau of Economic Research, it might carry some weight. Researchers reviewed data from 132 countries and found a happiness curve. Happiness falls after the age of 18, reaching its lowest point in the late 40s.

Sisters and tennis icons Serena Willians and Venus Williams shared an epic embrace after winning the Olympic gold medal for Women’s Doubles Tennis in 2012. “We are captivated by images of people hugging because our own mirror neurons feel a sense of connection we see others hugging–in other words, it’s like receiving a virtual hug,” explains Lauren Cook, a therapist, author of Name Your Story: How to Talk Openly About Mental Health. A hug is an indication of social reciprocity, warmth, and caring—all indicators that humans crave in their social connections. It is natural that we crave these close connections and feel a sense of joy when we see others hugging as well.

Blame your boss, the weather, your period, whatever—it’s 100 percent normal to be in a bad mood every now and then. (Yes, even for people who go to yoga four times a week and sip green tea instead of coffee.) Even happiness therapist and The Sunny Side Up author Lauren Cook wakes up on the wrong side of the bed sometimes.

“Sunday is supposed to be a day of rest and relaxation, but it can easily become a day of worry and anticipatory anxiety,” says Lauren Cook, MMFT, therapist and author of “The Sunny Side Up! Celebrating Happiness.” “Our culture places increasing value on being ‘busy’ and productive — and that takes a toll on our minds and bodies.”

How, though, can we stop Monday dread from ruining our precious Sundays? I needed a game plan, so I asked the experts about giving this special brand of anxiety the boot.