Molars & 2-1 Transition Nap

My daughter has slept through the night since she was 6 months old after going down at about 6-6:30 at night and usually waking at 7 sometimes 7:30 in the morning. Since her 12 month checkup when the doctor said she could see her bottom molars trying to make their way through, she has been waking up once at night (not every night, just usually once a week) crying and sometimes inconsolable. I thought at first it could be night terrors or a bad dream because she would be terrified for me to put her back in her crib after she calmed down and would lay her head on my shoulder eventually falling asleep. But when she was crying the other day I saw that her one molar had officially broken through so I thought we may be in the clear until the next teeth come through. However, last night she woke up at 12:40 am and didn't go back to sleep until 4 am after I gave her some warm milk- I haven't had to give her a night time feeding since I stopped nursing her right at 6 months. She also has gone to one nap- it starts at about 11:30 after she has lunch and she sleeps for 2 to 2 1/2 hours with the same bedtime at night. Could the wakings be from her molars or the transition to one nap? Or is it a combination of both? Have any of you Mommas out there experienced anything similar? Advice and reassurance would help so much!!