Cool down , be patient and relax.
All these symptoms seem to be symptoms of drug induced gastritis; because you would have been prescribed some anti inflammatory drugs for pain in the last 6 wks. As there is no signs of blood stained vomiting
and tar color stools, you need not worry about internal bleeding
.Consult your doctor whether to continue the clexane
or not.Till then you can take antacids and proton pump
inhibitors which can give you relief from pain and anxiety