You need to keep using it, if you stop using it the Virus level will go back up again.
There are only two stopping points:
1. HBEAG+ patients. - when taking medication and some seroconverts from HBEAG+ to HBEAG- and develops HBEAB (anti bodies)
2. HBEAG- patients - when clearing HBSAG, there are some articles on studies of people trying to stop sooner, like after being undetectable for 2 years but many people relapse
Either way it is too soon for you to stop.
No, it is not advisable to stop taking the medicine, even if your hbv dna level is undetectable. The antiviral treatments only help to suppress the replication of the virus, but do not cure the disease. Once you stop taking medicine, the virus replication rebounces, in most cases much stronger that could damage your liver. If, in any case, you decide to stop treatment, then it must be done under strict monitoring to see if there is any rebouncing of the viral replication.