Hello, welcome to the forum.
I was changed to Toujeo some years ago by my doctor as Lantus was being withdrawn by Sanofi, it was a cost decision I was told.
My main problem with Toujeo was that it could not be split into 2 doses as Lantus could. This gave me some problems at first and I did have some trouble. I was told by my doctor that I must use the same dose as I did Lantus, 18 units, but I split Lantus into 2 x 9 units. I had problems so I telephoned Sanofi in Barcelona who confirmed that I could not split it. After a while things were obviously not right and so I reduced gradually to 15 units taken in the evening. I have now changed to taking it in the morning with very good results - so far - but this morning I reduced it to 14 units as I have been having low readings in the mornings. I'll know tomorrow morning if that decision was the right one, or maybe the day after.
I also learned, quite recently that whilst Toujeo must be kept in the 'fridge before it is used once you do start a new pen it must not be put back in the 'fridge but kept at room temperature. As far as the cold-like symptons are concerned I too have had, and continue to have, much sneezing and nose-blowing first thing in the morning. May I ask which Province you live in?