I feel your pain girl. I'm 8 weeks this week and feel like I can sleep for days if I could. I found that exercising works best. Getting your heart rate up even when you really don't feel like it. You will feel like a million bucks after. My go to food right now is fruit because of the natural sugars and fiber. I have found it to be really helpful with feeling better and having more energy. Fruits like grapes, honeydew, oranges, and bananas take amazing right now for some reason!
I'm also 6 weeks 3 days, and so tired! I'm a SAHM with a 4yo and 2yo, so I can only nap when they do, which is for 1-1.5 hours in the afternoon. Usually, I'm having a hard time keeping my eyes open by 10:30 am!