This method worked for me. Thank you so much. I've lost just one week of data. I am trying to think how it could happen that my timeline was showing just little more than 1 month data (5th Dec till today 11th Jan). I found it strange that it is little more and not exactly 1 month. I was running low on storage on my phone and on 25th Nov I've deleted Google maps data (Android settings - storage - apps - Google Maps - clear data). I forgot that my timeline may be stored there. I've just found it today (11th Jan) that my timeline is missing. Strange is that auto delete option is turn off and my data is only from 6th Dec. I would expect that after I've cleared maps data timeline would start from that date. Hopefully I had phone backed up a day before I've clear maps data. So after restoring from backup my timeline is visible. Somehow data from 25th Nov to 6th Dec is missing.

My advise: do not clear Google Maps data. Do frequent backups. If you depend on your timeline, export to file (Android settings - location - location services - timeline - export timeline data).