Your credit score is affected by the accounts and credit history on your credit report. If the information in your report stays the same, your credit score may not change either. Even if there has been a small change to your report, this may not be enough to impact your score straight away.
Building your credit takes time; you may not always see an increase every month. To help you take action where it matters, look through the 'Impacting your score' section of your report.