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Since you have had regular menses after the act of sexual foreplay that means you are not pregnant.The nausea;heartburn
is probably due to acidity and gastritis
so you can take antacid like Ranitidine
300 twice a day and tablet Domstal (domperidone
) 10 mg 3 times a day and you will be fine.But one thing to remember is that even the clear liquid which comes out from penis which is also called precum can contain and can result in pregnancy
so you should avoid the touch of penis near vagina and even take care not to touch your vagina with the hand that you have touched the penis.