That sounds really difficult, I’m sorry you’re going through this. I think the pregnancy tests they use at hospital are not very sensitive - when I first went in I’d had 3 positive tests yet they told me the test they did was so faint it looked like a negative. They took bloods and my hcg was low (just 72). hcg went up steadily over a couple of weeks before I was finally diagnosed with an ectopic.
If you feel well and can stand the wait, I’d probably test again but maybe in a week rather than every day? Or ask for a blood hcg test to put your mind at ease. I hope it all works out and that it’s just taking some time to drop following your surgery. X