Ubuntu – No network devices available – Ubuntu 16.04 (No wifi/no Ethernet)

I'm new to Ubuntu and I would appreciate your help.
So, I used wire connection and it worked perfectly well, and with no obvious reason it just stopped.
I tried to reboot Network manager. I changed my /etc/NetworkManager/NetworkManager.conf to managed=true but still don't have any connection.
'System Settings/Network' gives me only 'Network Proxy' (neither 'Wireless' nor' Wifi' options).
When going to 'NetWork Connections' I see some of 'Wifi' connections I had before and one 'Bridge' named 'docker0'. (I used to work with docker, never had any problems before).

EDIT: here are some frequently asked commands I've tried:

ushakova@ushakova-HP-Notebook:~$ ifconfig 
docker0   Link encap:Ethernet  HWaddr 02:42:5c:b9:d1:e8  
      inet addr:172.17.0.1  Bcast:0.0.0.0  Mask:255.255.0.0
      UP BROADCAST MULTICAST  MTU:1500  Metric:1
      RX packets:0 errors:0 dropped:0 overruns:0 frame:0
      TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0 
      RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback  
      inet addr:127.0.0.1  Mask:255.0.0.0
      inet6 addr: ::1/128 Scope:Host
      UP LOOPBACK RUNNING  MTU:65536  Metric:1
      RX packets:4972 errors:0 dropped:0 overruns:0 frame:0
      TX packets:4972 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1 
      RX bytes:373328 (373.3 KB)  TX bytes:373328 (373.3 KB)

ushakova@ushakova-HP-Notebook:~$ iwconfig 
lo        no wireless extensions.

docker0   no wireless extensions.
ushakova@ushakova-HP-Notebook:~$ vim /var/lib/NetworkManager/NetworkManager.state

[main]
NetworkingEnabled=true
WirelessEnabled=true
WWANEnabled=true

ushakova@ushakova-HP-Notebook:/etc/NetworkManager$ vim NetworkManager.conf 

[main]
plugins=ifupdown,keyfile,ofono
dns=dnsmasq

[ifupdown]
managed=true



ushakova@ushakova-HP-Notebook:$ lspci -knn | grep -EA2 'Eth|Net'
02:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller [10ec:8136] (rev 07)
Subsystem: Hewlett-Packard Company RTL8101/2/6E PCI Express Fast/Gigabit Ethernet controller [103c:8305]
03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter [10ec:b723]
DeviceName:  
Subsystem: Hewlett-Packard Company RTL8723BE PCIe Wireless Network Adapter [103c:81c1]

ushakova@ushakova-HP-Notebook:$ rfkill list all
**NO OUTPUT**

Any ideas? Thank you!