I worked overtime at an Amazon warehouse in the run-up to Christmas. It's like being in the gym for 10 hours straight, six days a week.

• An Amazon worker told Insider they got depressed after working six days a week before Christmas.
• The worker said after doing it for 10 weeks they "lost hope of having a normal life."

This as-told-to essay is based on a conversation with an Amazon warehouse worker in the UK who spoke anonymously to protect their privacy. Their identity and employment have been verified by Insider. The following has been edited for length and clarity.

My role at an Amazon warehouse is in inventory control. It involves counting how many items are placed in a bin or pod – where items are collected – scanning barcodes on items in bins, and keeping recording of how many of the same items are placed in each bin.

All of these three tasks are called counting. I also keep a record of damaged items by going around the warehouse floor and collecting them onto a trolley, entering them into a system and then sorting them.

Some of the items are sent to "damage land" – a place where we keep damaged items that can be sold at a lower price. As inventory control falls under the quality department, I also check for mistakes, such as items being put in the wrong place.

Collecting damages means having to walk all night around a huge fulfillment center. It's physically demanding because items can be heavy.

In the run up to Christmas, it's very tiring. People are stressed out and it's not a good vibe.

We get paid more money, but overtime is compulsory.

In non-peak times, I work 40 hours a week across four days. In my contract, it says that Amazon has the right to change our schedule, so when peak season starts in November, managers inform us during a briefing at the start of each shift of any schedule changes.

I was told in a briefing that it is compulsory to work five shifts a week in peak season, rather than the regular four shifts, and workers can also volunteer to do a sixth shift.

Last year's peak season was really hard

I volunteered to increase my overtime from five to six days because I wanted to earn more. My husband wasn't working at the time so I did that for 10 weeks. After that, I got sick and couldn't do anymore.

I had sore muscles, aches and pains. A ten-hour shift is like being in the gym for ten hours because bins and pods are huge, which means you're going up and down a step ladder to reach the top.

I was exhausted. I had no life outside of work and was constantly physically and mentally exhausted. I felt depressed. I didn't want to see anyone, including my husband and son.

On my day off I just slept. I barely saw my son and would only have a short chat with him before or after school. I lost hope of having a normal life. If you only work and sleep, how else can you feel? I felt depressed and cried every day.

I couldn't leave the job because I was the only one in my family working

It was a bad time and I was constantly tired and angry. I didn't have the energy to do any cleaning or chores. All I could think of was sleep.

I didn't see any friends until after Christmas. When I went back to doing four days a week I was still exhausted. It takes time to recover from burnout.

I wake up around 4 p.m. when my son gets home from school, make him some food, get showered, and I'm out the door by 5.15 p.m. because my night shift starts at 7 p.m. I finish at 5.30 a.m.

It gets busy in the period around Black Friday and Cyber Monday but it's worse closer to Christmas. Pods, where items that are sorted and are being prepared to get shipped out, are full during peak season. There's no space on them and we're working under pressure.

The greatest challenge is having new people join as temporary workers to help cover the peak season. It's a disaster because new workers don't know all the rules. It makes it harder on other people's jobs because it means having to fix their mistakes.

As they're temporary, new people don't tend to care about their work as much because they know they'll eventually leave so they don't take great care with items.

In the peak season the canteen is the worst as there's around 200 people at a time waiting to use the microwave, purchase food, or use the vending machines. The food is disgusting so I bring my own. When the canteen is that busy, you lose 10 minutes waiting in line to use the microwave.

I'm now doing five days a week, which I'm contractually obliged to do, and it's still hard and tiring but I'm not volunteering for an extra day of overtime this year.

Night shifts are tough and it's a physically demanding job and you have to walk a lot. In the morning when I get home I don't have the energy to do anything. I just want to have a life.

In response to this warehouse worker's comments, an Amazon spokesperson told Insider: "Working in a warehouse is not for everyone. But for those who don't want to sit at a desk all day, it's a hugely rewarding job."

They added: "The fact is, if you want to work in a warehouse, you'll want to work at Amazon. In addition to offering excellent pay and benefits we ensure everyone is supported, treated with dignity and respect, gets regular breaks, and works at a comfortable pace. See for yourself by coming on a live tour."