HELP-can’t get rid of ammonia in tank

Everything was going super well for the first week after my tank was cycled. I got a few fish, tested 0 ammonia every day for a week, so I got a few more. I had a snail pass away and it was in there for a while, so I’m not sure if that caused it, but my ammonia is sitting at 0.25 ppm now every day no matter what I do. I’ve water changed, used prime, added more beneficial bacteria, nothing is working. I have 0 nitrites and about 5-10 ppm nitrates. I’m so nervous for my fish and shrimp, especially the shrimp, and I’m not sure what happened. If I added fish before the tank was actually finished cycling, what can I do now? I really thought it was, and now I just want to save this. Please help. I know I messed up but I really love my fish and I just want them to be okay 😔