While it is perfectly ok to be sad at the loss of a pet for a while, and to want to do things to prevent any further losses, that level of anxiety (months later, feeling antsy and HAVING to check on them/spend a certain amount of time with them) does not sound exactly “normal”

. Do you find you have anxiety issues in other areas of your life as well? Have you talked to your health care provider about this issue?
I also agree that providing a secure run for them and only letting them out to roam when it suits YOU may alleviate some of your anxiety.