Hi hon. I think that is fantastic you are working on losing weight. It's so hard. Supposedly weight can affect getting pregnant--- but probably not much with being underweight more of an issue than overweight. I gained weight on purpose when my husband and I tried to conceive. Not because I probably needed to but I was a tad underweight (where, THAT was a long time ago . . you should see me now, ha ha) and I was willing to do ANYTHING to get pregnant. The best thing is to track your cycle. WEight gain or loss can affect our hormones and change our cycle. Normally our cycle will get a bit longer during these times but ovulation becomes a bit unpredictable which makes conceiving on purpose harder. So, watch your cycle and see if you have a regular one. I used a chart to do that. Now there are awesome apps to do it (
medhelp.org has a great one called Mycycles which you can find in the above toolbar under health tools). My doctor said the best way to conceive is to begin tracking our cycle with day one of period being cycle day one and then on day 10 of your cycle, begin having sex every other day for the next 10 days and keep going every other day if your cycle is longer than the average woman.
Let us know how it goes and we have a trying to conceive community here that you can find under communities -- again, at the top toolbar. good luck