Thank you for your query.
Firstly, as the tests are negative, you are certainly not pregnant.
At 43, I think you need to take the help of an IVF specialist.
However, as you conceived a year and a half back, you have good chances of conceiving again.
Please remember, that as maternal age advances, chances of chromosomal disorders ( like Edwards ) increases.
Have evaluation of your ovarian reserve
, your partner's semen analysis
, genetic counselling
and then proceed ahead with the treatment advised by an IVF practitioner.