Migrated from Meteor 1.2 to Meteor 1.8 resulted in extremely slow performance

I just migrated my application from Meteor 1.2 to Meteor 1.8 (Angularjs).

My application is extremely slow, I am fetching 20 records per page, and it loads like half of the records and then it gets stuck.
After that I have to kill my application, and relaunch, it works fine for 5 or 10m minutes max and gets slower again.
There is no error on the server terminal or browser console, what could be the issue here?
Is there any way to debug this? So that I can know if there is some issue with my queries or code that is causing this issue after migration?
For the record I am still using Angular 1 on client, since I have a huge web application.