Welcome to HCM,
test is either positive or negative. There is nothing like slightly positive.
Before pregnancy test you should have asked your husband to get his semen tested for confirmation of vasectomy
You can become pregnant only if sperms are present in your husband's semen.
As next morning sample was negative, reliability of previous reading/result is doubtful.
Some times bleeding can prolong due to hormonal
In my opinion it was not a miscarriage
Thanks for trusting Healthcaremagic and posting your query.
Hope you found my response to your query informative and helpful.
If you have further concerns in this regard, you can submit those with Healthcaremagic as well.
With good wishes,