Thank you for asking.
Your complaints are strongly suggestive of anxiety problem. A General anxiety disorder(GAD) or Obsessions (OCD). Not able to concentrate, pondering upon general thoughts, excessive worrying, not able to relax or sleep, headache, bodyache, low mood, etc are few associated symptoms.
It is completely curable.
A consultation to a psychiatrist is strongly advised.
Treatment: therapies such as CBT, relaxation techniques, lifestyle modifications.
If needed medications can be required.
Hope you find this helpful. For more information contact me directly on practo.
Regards
Dr Pankaj Borade
Next Steps
Consult a psychiatrist.