If your doctor did a thorough check of your health and nothing abnormal , except that possible LA enlargement, came out the test, I would not worry about it too much.
EKG criteria are not very specific for LA enlargement so if you are further healthy, your LA is probably just fine.
LA enlargement can be the result of hypertension or from i.e. a leaky valve.
I guess your doctor did measure blood pressure?
A leaky valve can be detected with a stethoscope.
If you keep worrying about it, you could ask for an echo to rule out the LA enlargement.
Don't worry about it if the doctor said it's fine. EKG machines interpret the results but it takes a doctor to make the final determination. Missing a few doses would have literally no impact at all.