Irregular could mean just an irregular shape
Dont' stress. If there was something to worry about they would have told you to go straight back to your docs.

How many weeks are you now?
When is your next doc appointment?
Can you take someone with you as a second set of ears - just in case you forget something. Also write down any questions that you have - you always forget them when you get there
Good luck and let us know how you are going