Has anyone had issues with ttc while underweight and then gained weight and conceived?

My BMI is currently 17.6. Since ttc I have been trying to gain weight. I’ve always been underweight and I don’t have an eating disorder but I’m rarely hungry and get full quickly. I used to just have a small sandwich for lunch and something like chicken and fries or pasta for dinner, I don’t snack and I don’t like any sweets/chocolate.

So far since ttc I’ve made the following changes:

Started having breakfast (a homemade smoothie with about 7 or 8 kinds of fruit and natural yoghurt)

Having a nature valley bar for a snack almost every day

Having home made soup with brown bread for lunch

Added vegetables to my dinner aswell as having more home made dinners instead of frozen

Added more red meat to my dinners

I do still have some ‘unhealthy’ foods sometimes like pizza or a chinese take away..

I’ve started taking prenatals, I’m not sure if that would help me gain weight but it’s added nutrients right?

I do some light Pilates at home some evenings, nothing too strenuous.

I’ve actually lost weight since ttc and I’m really at a loss as to what else I can do, I really can’t force myself to eat anymore than I am at the moment.

I’ve only been ttc for 5 months and I know it’s not long but I really think this is holding me back, has anyone else ever had this problem and have any ideas? Also any good foods to add to my diet that will help with conceiving? 😊