Total lack of energy... what else can I do?

[PourquoiTuGachesTaVie]

I'm 18 weeks and so very tired. I've had to have a nap for an hour or two for the last three days - including today and I wasn't even in work today so that's no excuse.

I have a 3 year old and need to be more awake than this!

I'm taking seven seas pregnancy vitamins, which include iron.
I'm doing at least half an hour of brisk walking done every day as exercise. I'm trying to drink plenty of water but I'm restricting the number of cups of tea I have so I'm missing the caffeine a little I think (I don't drink coffee anyway).
I'm trying to have a reasonably balanced diet, but I'm also craving bread and potatoes a lot, and I wonder if this is related to how tired I am?

Is there anything else I can do?

Ds keeps asking "Are you still very tired?" and getting me blankets and cushions. I have bad mummy guilt!

Thanks for the tip about the vitamin C, very useful to know.

Rest when you can. No other helpful advice. Am 38 weeks now and been shattered for the last 34... Sorry!

I'm 18 weeks and completly dead on my feet as well. Four kids and a full time job and it's really taking it out of me this time. I need to work out how to sleep with my eyes open!

Brian go take a nap... I'd watch the kids for you - there's no way I could be as tired as you!

I'm in bed as soon as I get the demon 2 year old to bed so not quite falling asleep at work yet!

I also feel the same I'm 23 weeks and so tired. It never went away with my first son I was exhausted all the time, ended up leaving work at 28 weeks for mat leave x