It is important that you pace yourself in your studies and that you plan out certifications. Having said that, if you're on a win streak with your current methodology. Then most us try and continue that to keep it going even to the point of exhaustion.
The issue comes down to you cannot keep sustained focus on all the ones you've got listed. One of them will become less important to you. So the way you do this is prioritize what you want to get now. Do that one certification before beginning on another. Most cannot do a "split-focus" of many topics and do them well.
The other is give yourself breaks in each study session as well as time in between certifications. But the double edge sword is "time." If you go too long, you'll lose motivation or forget material. So you must be strict with it. I recommend 1.5 hrs of study,15 minute break, then 1.5 hrs again and 15 minute break.
If time management is not your forte. You may consider a topical approach. Challenge yourself to learn something new everyday about a particular topic you're studying. For example, in BGP, I'm currently learning about using
Unsuppress maps for traffic manipulations. This is not a timed element except for my configurations but conceptually understanding it by and making notes about it. I don't stop until I learn something new.
Lastly, between certification, Celebrate your win, with your eyes on the goal for your next certification. define your celebration specifically, then when you're done. Hit the books!