Troubled tomato leaves
I am growing a Roma tomato plant in a container on my balcony for the first time. I also have a cucumber plant growing next to the tomato in a container. About a month ago, I noticed some small holes in the leaves of my cucumber and then about a week or two later, I noticed the same small holes in my tomato leaves. The holes eventually seemed to get larger and larger, until entire leaves have disappeared, and just the straggly stems are left. The leaves that get direct sunlight seem to be the most affected. The stems and the fruit don't seem to be affected. There are also a bunch of small black dots that look like droppings of some kind. I thought they were bugs at first, but they don't move. I checked the tomato disease identifier and nothing seemed like this. I also did a bunch of research on the internet before I found this forum, and I thought some possibilities might be flea beetles and/or aphids, but I have never actually seen any insects on the plants - the tomatoes or the cucumbers. I also tried looking for the dreaded tomato hornworm, but I see nothing on the plant anywhere. I don't know if this is relevant at all, but one of my two fruits has blossom-end rot, and I haven't had any blossoms turn into fruit since those two appeared about 3 weeks ago. I'm not clear on how much I'm supposed to water, so I water every morning, maybe 3-4 cups of water. There are also some leaves that are just turning yellow, without any of the holes.
Since this is the first tomato I've tried to grow, I'm a little discouraged, and if someone knows what this might be, I would SO appreciate any advice so I can avoid this in the future. It's so discouraging to see a bushy, healthy plant completely fall apart. I attached pictures of the holey leaves, the black specks on the stems and leaves and a picture of the yellowing leaves without holes.
Thanks in advance for any advice.