Feeling sad and discouraged

I am currently ttc baby 2... my first baby was conceived when I was 5 foot 6 and 205 pounds... we conceived her within 3 months of trying.. she is now 19 months old and I currently weight 237 pounds so haven't lost much of the baby weight.. we have been ttc baby number 2 since march it has been about 5 months and my periods are irregular and long but seem to come every 35 to 45 days.. I also have not been getting any positive ovulation tests but I'm using the cheapies from Amazon.. I test twice a day from cd 10 to cd 25 but never get an actual blazing positive.. the line seems to get a little dark but never as dark as the control line.. i feel so sad because I know it's my weight which is causing these irregular periods and keeping me from ovulating... I feel like crying 😭 I just want to get pregnant so badly and I feel so fat.. I keep trying to diet but am so unmotivated but keep telling myself I can do it.. it was just so easy to conceive #1 that I'm in shock that it hasn't happened again.. would love some words of encouragement or tips.. had to vent 😞😔