So, I Have A Disease Called Lupus, And Im Divorced

so, I have a disease called lupus, and Im divorced as of a couple of months... howveer my ex husband and I got togetehr in june and had intimacy, my period for july came as normal as it can, but now my august one has not come yet...so im worried I might be pregnant cause it can affect my health, I have done 3 home pregnancy tests all negative and 2 blood lab tests allso negative.... but I was kind of diagnosed with OCD, so i dont know if its my ocd kicking in or my worries are realistic...