Small baby bump

I've been told by my mother that I'm not showing that much and I should be showing more. I lost a ton of weight before pregnancy. So much weight my ribs showed and my stomach caved in. I didn't know I was pregnancy cause for the first 2-3 months I wasn't seeming to gain weight. I didn't have much morning sickness. Some nausea and just overall tired. I would throw up maybe once or twice a week. When I started seeing a huge change in my breasts, I spotted for 3-4 days, my mood swings were off the wall and my once caved in stomach wasn't so much caved in any more I took a home pregnancy test, sure enough I was pregnant. Around weeks 8-9 I was 97 lbs. At week 22 I weigh 117.6 lbs. I gained about 4-6 lbs each month. My mom really believes that something is wrong because my stomach isn't showing that much when she saw me early in the morning before I ate. In the mornings my stomach is smaller than when I went to bed. Even with that said my husband tells me that that early morning small bump is even getting bigger. In the mornings I can see my toes while as before I go bed, my feet are invisible. I need help understanding if I'm the only one this happens to cause the midwife I had before I moved said that it's normal. Does anyone elses stomach get bigger throughout the day? Should I be concerned like my mother? Or is the midwife right and it's normal?