My normal tomatoes fruited at cherry tomato size for some reason :( I got a few maybe an inch and a half wide, but since then the rest stop and turn red earlier

My normal tomatoes fruited at cherry tomato size for some reason :( I got a few maybe an inch and a half wide, but since then the rest stop and turn red earlier. No idea what the problem is, maybe it's fungal. Quite a few leaves were turning yellow/black lower down.