Choking during nursing

[fhdl34]

Hoping someone can advise me before I decide to remedy this myself (that might be what got me into this pickle in the first place - sigh!).
Over the last 3 days or so, my DD has started choking during feeding (not every feed but a few times a day) and also getting a lot more wind (this may be connected or just coincidence). On Friday, after reading a thread on here and being told by my HV that DD would be due for a growth spurt, I decided to change from feeding from 1 breast per feed to offering both at each feed. I'd let her stop herself and then plonk her on the other one.
She definitely getting more bad tempered whilst nursing over the last 3 days, she either chokes, or pulls off and cries, wants to go back on but won't latch.
I just googled choking during nursing and it brought up that I might have oversupply but my nipples don't leak or hurt and when she pulls off, she gets a good dribble down the side of her face but it doesn't spurt out of my boob anywhere.
Anyway, I read that if it is oversupply I should offer 1 boob for all feeds during a 4hr period and then swap to the other boob but I don't know that I have oversupply so don't want to change what I'm doing to cock it up anymore.
Am annoyed with myself that I changed what I was doing in the first place because she was happy before; I only changed it because my HV had concerns because she'd only put on 5oz in a week and she said she should've put on 7oz. But I felt everything was going fine.
Can anyone give me any advice to get my baby back to being a happy feeder and then I swear, if I think she's happy, I'm going to stick with what's working.
BTW, DD is 18 days old if that makes a difference.

Congratulations on your DD! Chances are someone who knows more will be along shortly, but until then (or even as well), whenever I have used any of the breastfeeding helplines I've found them incredibly helpful. They'd be able to talk you through whether you might have an oversupply, and suggest some things you could try (whether it's that or something else).

Thanks redkites, I just tried 2 of them but got answerphones. We have a local breastfeeding support group so I rung them as well and left a message so hopefully someone can help me soon. She woke 45 mins ago so offered her the same side she'd fed on an hour before that and she seemed calmer bu might be a coincidence. She's still making a lot of noise and smacking her lips.

That's frustrating, but they are staffed by volunteers, so it's inevitable it will happen sometimes. I hope you've managed to get hold of someone by now, but if you haven't, it might be worth trying again this evening (as anecdotally I've heard it's easier to get through in the evenings - presumably more volunteers about?).