WEIGHT GAIN TIPS?

Any tips on weight gain and increasing appetite? I’m struggling to gain and my two year old isn’t completely off the boob so I can’t take weight gain supplements. I’m 119 right now and 138 to 155 is more of a normal weight for me. Doctors typically don’t seem concerned about my weight because it’s consider accurate for my height BUT I was 165 and dropped to 116 (my lowest) in about two months. Someone please help! All advice appreciated. I’ve been struggling to gain my weight back for over a year. I typically eat 1-3 times a day but it’s a struggle because some times I’m legit not hungry.