Does an arrhythmia usually make you feel short of breath and tired?

Possibly: It's possible but many things can cause these symptoms. To check for arrhythmias, feel the pulse when symptoms are present- is it regular? Fast (well over 100 beats per minute)? Slow (well under 50-60 beats per minute)? If so than it's very possible that an arrhythmia is the source of the symptoms.

Yes: Due to heart not relaxing enough during arrthmia not enough oxygen coming into body so you can feel breathless.