Hello
If you can log in to Facebook, under the Settings > Security > Active Sessions. I would Log out all sessions that you do not recognise - (see attachment).
[attachment=4273]
For your Facebook account, under the Settings > Apps. I would Remove all apps that you don't use, or never seen before.
Also for your Android device, I would check to see if you have any disguised malicious Apps and remove them. You can scan using VirusTotal to see if they're suspicious or not.
https://play.google.com/store/apps/details?id=com.virustotal
Hope this helps.