Ttc #2 soon but?

Okay so my daughter just turned one a couple weeks ago. My husband and I are going on a cruise in may and are discussing possibly trying again. My issue is I want to gain some weight before and I'm not sure how with chasing after a toddler all day every day. I'm more concerned because with my daughter I got very sick and lost 11 pounds the first trimester but gained it all back and then only an Additional 17 Pounds and she was a healthy 7 pound 8oz baby...I'm skinny by nature. This time I'm 5/10 pounds less since LO started getting mobile in the last 6 months. What are good ways to put on the weight and keep it up as I'm going to need it If I get sick again. Also it took us about 8 months to get pregnant with her...did any second time mom's find it happened faster with subsequent pregnancies?