You don't have to set timestamp if you call to WriteSeriesData as the points come in, it'll be assigned automatically. Sequence number will always get assigned automatically.

You should be using the objects from protocol.pb.go. Basically, create a series object, columns, and then points. Create field values for the points. Timestamp and Sequence number should not be their own fields.

This might give you a better idea:
https://github.com/influxdb/influxdb/blob/master/src/common/serialize_series.go#L56-L132