welcome to HCM.
Frottage sex doesnt involve penetrative sex. If in case U had a penetrative sex, only then is there a possibility of ejaculation into ur genitals & u being pregnant.
please get a UPT(urine pregnancy
test) done by urself,which is available in any pharmacy & get a confirmation on ur pregnancy & get the doubt cleared.
If not, wait for a full cycle to complete & if the spotting again persists in the second month, kindly consult a gynecologist for a thorough examination.