Mental stress is impacting your physical health so first you need to address your overthinking. Overthinking means that you're living in the future, Practice Being in the Present moment. Be mindful of each and everything you are doing right at this moment.

For example: suppose you are eating chocolate, focus your attention on the sound of the wrapper while opening it, and then focus on how chocolate is melting slowly in your mouth... Similarly, be mindful of whatever you are doing in your day-to-day routine.

Deep breaths can change your state of mind immediately. Breathe in through your nose and out through your mouth. Make your exhale longer than your inhale. Write down your problems, which gives you a chance to make sense of them and come up with a solution.

Once you realize there's a solution, your overthinking will lessen. If your depression is severe then you require medications along with counselling.

Hello... Yes! Depression is a very common mental illness in which the patient has a low mood low energy, and no interest in activities that he used to do earlier. Patients also don't sleep well and their food intake also reduces., Sometimes they may feel as if the future is hopeless. Patients occasionally have suicidal ideation also.. but fortunately, it is a very easily treatable condition with drastic improvements in mood and other symptoms with medications. sometimes patients may be suggested therapy with medications also. Contrary to popular belief it is not a weakness of personality. Please don't ignore the pain of anyone going through this. Seek help immediately.