A lot of things get called systematic reviews without actually being systematic reviews. Simple literature reviews, for instance, might aspire to the badge. But systematic reviews do more than simply identify and summarise existing publications. Definitions vary but high quality reviews usually aim to answer a research question by:
identifying all relevant published and unpublished evidence on the subject of the review
selecting studies for inclusion
assessing the quality of every included study
synthesising the findings from all of the studies in an unbiased way
presenting a balanced summary of the findings.
High quality systematic reviews of complex questions can involve large teams of researchers and can take months or even years to complete. It is accepted good practice to have at least two researchers working on any systematic review to minimize bias in the selection of studies — Cochrane Collaboration reviews, for instance, cannot be produced by individuals working alone, as the selection of studies for eligibility and data extraction has to be performed by at least two people independently.
The resources you have and the time available to you will dictate what level of review you can reasonably hope to complete, so if you are working alone, and have a short deadline, you need to discuss with your supervisor exactly what they expect you to produce.
You can read further information about systematic reviews in the following links: