Sex 10-15 times in three days is a bad idea, especially if you haven't had sex in a while because things tighten up and need some stretching. The body isn't meant for that. You probably bruised yourself badly.
Since he is your fiance I am going to assume he loves you. If he does love you setting limits is healthy. If it hurts, you stop, period. You can always finish with masterbation. If you don't talk now about your sexual feelings you will be trapped in a marriage where you don't get your needs taken care of. If you are not orgasming, he is not being a good partner to you. You may not orgasm every time, and certainly not every time if you are doing it 4 times a day, but you should have them regularily.
You should get the pain checked out by a doctor. It is likely nothing serious, but could be a bladder infection or vaginal infection from all the irritation. Pain, blood, and nausea should always be checked out. It could even be unrelated to the sex, you should get checked out.
And your mother would likely rather be there for you, than not. If he is your fiance, they at least know you have a committment to each other and it isn't a one night stand.
Your mom may not react 100% positively. I don't think parent's like knowing their babies are growing into women, but her love for you and your well being is important. You don't have to tell her everything, but my guess is she'd want to be there for you.
Take care as best you can, and if the pain and bleeding persists please go and see a medical doctor.
Hi Rocky, just get to a doctor or clinic ASAP and get checked out, its time to be honest with your mum, remember a mum is a girls best friend, so how does your b/f get to you if as you say your in the middle of nowhere. you really some help and you must find a good lubrecant for your sex endevers, and he was proberly hitting your uterus, but you need to take your time with sex, its no good for to just keep bashing away at you, he may think hes doing well, but sex is a 2 way thing and you both need to enjoy it.
Good Luck