Uncomfortable after eating

I’m almost 18 weeks and I’ve been finding that after I eat (especially lunch) I get very tired and extremely uncomfortable, it’s aggregated by sitting or standing. Like gravity is pulling my belly out and down. I feel slight relief when I use my hands to push/hold my belly in. Laying down is the only thing that takes that feeling away. I read that it’s due to slowed digestion, relaxin, increase blood flow, etc. Maybe I need to wear more supportive clothing? Anyone else experiencing this? Plus the urge to sleep is off the charts after I eat! I could fall asleep standing up!