thanks for your query
1-you had your appendex removed about three months ago.
2-two days after your period during innercourse you had wasgushing out blood then right after you stopped bleeding .you also have blood clots
3-a lot of blood in your urine
-your complain have no relation to appendex surgery
-you have clot during bleeding it may be due to remaining blood clot in uterus
and which causes severe bleeding due to opening of blood vessel after stress
like sexual intercourse.
-check your sonography
report you may have some problem in kidney
like renal stone
get all investigations and thorough examination done .
with best regards
DR G C OJHA