Csgo server lags without reason
 

Hello, i have 2 csgo retake server hosted at home. i had no problem like 1 month both servers were full but there was no lag, now its started lagging even when there was 2-3 playeres increasing ms to 150-200 than goes down again and repeats this many times. even i got same ms like others but im connected from lan. sorry for my bad english.
i use different pcs for hosting amd playing. hostpc: i5 3.2 ghz 6gb ram 80-90mbps internet. checked in resource monitor no cpu usage its like 30-40% when both servers are full.checked also internet usage it was same. also when lags started checked internet speed and it was same downloas and upload what was before. can it be ddos? cas im from georgia and there was only 2 csgo when i created my servers they lost players and my servers where full all day.
plugins: latest sourcemod, splewis retakes, hpk lite, afkmanager, insta defuse.
sorry for my bad english.

using windows servers 2008 r2