Can GD be the reason I'm so tired?

This is my sixth pregnancy but first with GD. Also, I was younger with my others pregnancy. I'm 23 weeks and so so tired. I'm diet and exercises controlled.

Like when I'm standing up I just think about sitting down tired. Taking a nap everyday and sleeping 9 hours at night and still tired. To the point of saying no to activities because I know I won't enjoy it because of tiredness.

This is the kind of tired who doesn't get better if I push myself and move more. My husband says I'm so tired I even look sick sometimes.

My iron was ok, no anemia but a little low ferritine at 14 weeks pregnant. Take iron supplement. Gotta check it again soon. Talked about it with my doctor but she didn't seems concerned but agreed to make me time another iron test sooner.

Pre pregnancy I was pretty active. Now I'm still doing like 15 minutes of exercises in the morning and 30 minutes after dinner (indoor cycling) to keep my numbers in range.

I have tried eating a little more carbs the lasts 2-3 days wondering if that could be the reason. I follow the real food for gestational diabete 90 carbs a day usually. So trying to get to 100-120 a day, my fasting numbers became out of control the last two days because of it but my meals numbers are ok, juste a little higher.

So I don't know what to do right now. Never have I ever been so tired at the second trimester with my others kids. This time around, all my kids are sleeping all night so it's easier than ever.

Do you think the GD could explain it?