kamma wise why cant i do a steady practice

I have ups and downs in my practice (time doing formal mediation - time being mindful in daily life - doing good stuff avoiding bad stuff etc) and also ups and downs in completely mundane issues as well being lazy not doing anything for days to do stuff for my own benefit than doing lots of stuff (washing the house - exercise etc) than back to nothing ) I had times in the past where i mediated every day (in retreat but also at home) and times i did stuff like exercise study stuff etc now im in a slump for a few months doing almost nothing - i wonder how is it explained kamma wise .... bad kamma from the past ? lazy kamma ? is there no way to prevent this ? again asking from a kamma point of view - how to make a steady practice and steady good mundane stuff can be great (do i need some tipping point of good vs bad kamma done in this specific lifetime) but more than that WHY it happens also : how effective is current life kamma compared to past live kamma ? and recent kamma (1-3 months) in comparison to kamma made before (3months -99 years)