My friends think this is weird, but for me, it's perfectly natural

I hear both daily, though.

Although there are some words that really give me a tough time...

^ Same !!!!

My girlfriend is from northern Maine though and they don't have R's in their vocab at all lmao

However, I kind of pick up on the way other people say things, and sometimes my voice will randomly switch between different accents/dialects, so it's really a bit of both.

My mouth finds it really awkward to pronounce final 'r' sounds, lol. Or even the 'r' sound in words like "hard" and "park", which invariably become "hah-d" and "pah-k".


Some more info on rhoticity for linguistics-fans like me:

To confuse matters, sometimes us non-rhotic speakers do put pronounce final 'r' sounds.This is when a final 'r' is followed closely by a word beginning with a vowel.
Eg. The 'r' is pronounced in the phrase "water ice"

Furthermore, the funny thing is that while non-rhotics take out 'r's where they are, they also put r's where they aren't. These types of 'r' sounds are termed "Intrusive R"s and follow a bit of a random pattern. Examples:
Eg 1. "Drawing" becomes "drawring"
Eg 2. "The idea of it" becomes "the idea-r-of it"
Eg 3. "Australia and New Zealand" becomes "Australia-r-and New Zealand"