I felt a distanced from them and decided to sit in the back NO - NOT A PTOPER SENTENCE
I felt distanced from them and decided to sit in the back.
YES - but normally we would say "distant" (adjective)
"I felt distanced from them..." means they tried to keep you away from them,
e.g., They distanced you from the group OR The grouped distanced itself from you.
I felt DISTANT from them...
'to feel distant' does not refer to the physical distance that can be measured (kilometers/miles/feet/meters etc)
'to feel distant' is an emotional distance, the opposite of being close to someone
'distant' means 'not part of the group', 'not wanted in the group', 'not in a friendly situation'.