I don't think having a headache a feeling tired is anything to do with your diabetes. It's probably more related to having a little baby.
If you think your headache needs checking out, go to the doctor.
You say you've had no highs or lows but the highest you've been is 15. 15 is high, that's when my meter gets distressed at the result and tells me to check for ketones. If that counts as no highs for you I'm assuming you must have been seeing very high levels before. Well done on making moves to get in control, that takes a lot of stress and effort, it could also be stressing your body out a bit while it gets used to the change, making you feel worn out and headachey. Keep going with it!