Sounds like you might have a urinary tract infection. Best to have it checked out by a medical professional. If you do have a urinary tract infection, the right kind of antibiotics should clear it up.
In order to prevent something like this happening again, try changing your hygiene routine, e.g. after sex, don't lie there in each other's arms but get up and go to the toilet (urinate), dry yourself, etc. then come back.
Hi there. Yes, it does sound like a urinary tract infection, I agree. That there is blood in your urine takes it up a notch and you need to see a doctor soon.
Part of above is right in terms of hygiene, however it does not matter if you lay with your partner after sex cuddling or if you go to the bathroom but rather is an issue of keeping fecal matter away from your urethra. This means only wiping front to back and NEVER back to front and making sure your partner does not use a finger in your anus and then go to your vagina with the same finger or anywhere near your urethra. Same with sex, if you have anal sex, do not then have vaginal sex after without washing. These are the ways fecal matter are introduced.
But many don't have sex at all and get UTI's, and it is often a function of wiping. OR it is anatomical and has to do with things related to your bladder and kidneys which can also happen--- however, when this is the case, one usually has a history of frequent uti's.
good luck hon