Answer based on context:

After starting the season strongly, including a five-win run in September and October, the Chargers were beset by a string of injuries to key players, and eventually finished the season at 9-7. In contrast to 2013, the record was not enough to make the playoffs. The Chargers began the season 5–1, winning five straight after losing their season opener. It was followed by a three-game losing streak, and they finished 4–4 in the second half. They won just two of their final five games, coming back from double-digit fourth quarter deficits twice to remain in playoff contention. They lost the final game of the season when a win would have secured a playoff berth. In three of their last four games, and five of their last eight, the Chargers did not score more than one touchdown. Compared to 2013, the offense dropped in points (from 12th in the league to 17th), yards (5th to 18th), first downs (3rd to 15th), net yards per pass (2nd to 8th), rushing yards (13th to 30) and yards per rush (21st to 31st). It was the second time in three years the team finished second-to-last in yards per carry. San Diego was just 2–4 against teams in their division in the AFC West, and were swept by both the Denver Broncos and the Kansas City Chiefs. It was their worst intradivision record since they were 1–5 in 2003. The Chargers were only 3–6 against teams with winning records. They matched their 9–7 record from 2013, but missed the playoffs for the fourth time in five seasons.

What month did the losing streak start?
October