I'm on my second attempt at a large garden this year and it's the second failure.
Last year I broke fresh ground on my 20x30 plot. Which wasn't easy using a small hand tiller, (thank god for the lx and the 3pt tiller). We tilled the ground and applied some allegedly veggie safe weed and feed. All but 4 plants kicked the bucket shortly after planting. It was dry, but we watered about every other day. At the end of the year we retilled and nothing grew back.
This year with a dead patch of dirt and a new 3pt tiller I went after it a little late in the season but added some generic fertilizer only. I tilled it into the dirt, waited a few weeks, watered the ground and retilled just before putting the plants in. Everything was healthy and happy for about two weeks before out of nowhere the thickest weeds and grass you'd ever seen jumped up overnight and choked everything out. Im talking over two feet high in less than a week. Pretty much had to leave it as I could no longer discern between my vegetables anymore. This years crop was harvested today, only 3 cherry tomatoes and some jalapeños.
So don't feel down about a small harvest, it could definitely be worse.