You can check on your session usage from the reports>sessions tab on the web app and check the 'by subscription period ending' box. Your remaining session count may be lower than you expect for a couple of reasons,
- If you work on your mobile device a lot, it is possible that you ran over your session allowance the month before. Extra sessions are stored on your mobile until there are sessions available in your account, at which point your mobile device will sync and use up some sessions.
- You may have deleted some sessions. Deleted sessions are not credited back to your session count.
- Your subscription period may be off by 5 days. This happens when a credit card declines (say on the 1st of the month), then is successful when it automatically tries again 5 days later (on the 6th of the month). In this case your sessions are replenished the 6th, but your subscription period and thus the date your sessions start counting from still starts on the 1st.