Lost Zabbix data prior to June

Using Zabbix 3.4 and Grafana 5.1.3 with Zabbix plugin 3.10.2 on CentOS. We installed Grafana and connected the system via the Zabbix plugin last fall. We upgraded the plugin to 3.10.2 and now we can’t see any of the data prior to the zabbix plugin upgrade. I need to know how to view the data prior to the plugin upgrade. I didn’t make any changes to the database only just ran the upgrade from the command prompt.
Any help is appreciated.