I'm a girl of 17 and I am worried about my intimate parts. I'm too embarrassed to go to a gp in my local health clinic as the past two times I've gone they said I had thrush . But medicine I've had before hasn't helped and I don't want to go back because last time I felt like the gp didn't care and felt ashamed.
I've started more exploring my body and know it is important to be wet before I try to touch myself inside but even when I am well lubricated it still hurts to try even one finger and I have small fingers and even after it still hurts once I've tried. I sometimes get a discharge coming out and have been put on the pill because I had irregular bleeding. However even on the pill I sometimes get really dark browny blood when it is not my time of the month and tend to get tummy pain often.
I have never had sex and the most I have done sexually was have a boyfriend finger me almost 3 years ago and even that was very uncomfortable but I don't think it was as sore as it feels when I try sometimes nowadays. I'm to scared to use tampons when I have a period because the last two times I tried it caused me a lot of pain and even got stuck which was even more painful as I didn't know what to do and I do not have anyone I can talk to about this. I'm seeing someone who I think I may be sexual with one day but I am worried about any vaginal penetration because fingering causes me pain.

You need to talk to an OB/GYN, particularly if you may become sexually active.

Hi heatherbella
First, thrush is often called a 'yeast infection' when it's in the vagina. It might depend on what country you are in (I do in the US). Thrush is often used when it's in the mouth. Men get it in their penis too.
It is a yeast called candida. It is VERY common. You can get it just from the air, from a tiny scratch like from fingernails, from the acid balance (pH) of your vagina being off, or any number of reasons.
Yeast likes moist places away from air. People get it in armpits, belly buttons, under boobs, you name it!
It itches and emits a discharge.
USUALLY it responds to one treatment, but in a few cases, it takes more. It's simply a matter of telling a doctor. If one doctor was uncomfortable or made you feel bad, ask for a different one.

Now about brown blood between periods or even during, and pain, and tampons getting stuck, etc.
Brown blood is blood exposed to air before you see it. It is OK. But if you are bleeding between periods AND have pain, there are all sorts of conditions you could have, and generally a doctor would do an ultrasound. There's PCOS, fibroids, endometriosis, and others. They are all pretty common. They have to do with menstrual lining growing outside the uterus, in the abdomen, among other things.

Regarding tiny opening and just one finger - it sounds like you have a strong, intact hymen. They vary in thickness a LOT. Some are paper thin and break at the slightest pressure.

Regarding the boyfriend 3 years ago, if he was rough and had dirty fingers, or a tiny cut on his hand, his bacteria could have moved into tiny cuts inside the tender tissues of your vagina. Yeast and bacteria are NOTHING to do with each other. They each have different treatments.

Please assert yourself at the clinic! Make a list if that helps. It isn't fair to just shrug you off. Say LOOK, I'm in an unusual amount of pain! I need an ultra sound, more treatment for yeast, and another for bacterial infection! Some doctors will test for conditions, and others just give out the drugs and hope they work.

Changing bleached and boiled cotton panties, bathing a lot, air drying your pubic area as much as possible, will help along with the drug treatment.

Joy covered everything, I just want to add something about tampons. Young girls that are virgins usually buy a tampon that's much larger than what they need. They also use a tampon when one isn't really necessary. You're a young girl, and obviously very tight in that area, so a small tampon, one made especially for teens, is what you should be using. You should not be using a tampon unless your flow dictates the need for one. The first day of a girls period is normally light, so no need for a tampon, just use a pad. The second, third and fourth day are usually the heaviest, so use a tampon then. The fifth day is usually light or just spotting, so use a pad then. If a tampon is dry it will hurt pulling it out, been there done that, when I was younger than you and was too afraid to ask and snuck a tampon from my mom on the last day of my period so I could go swimming. I actually passed out from the pain, but the pain was from the tampon being completely dry, no blood on it at all. So unless you need to wear a tampon, use a pad instead. Only use a tampon on heavy flow days.

About the yeast infection, you do need to see the doctor again, or you can (if your country does this) go to the pharmacy and pick up an over the counter medication for yeast infections. Also, drink lots of water, and cranberry juice, eat plain yogurt with active bacteria in it. I can swear by both of these. Some people have said no sugar in the diet helps cure a yeast infection, as does garlic and apple cider vinegar. I haven't tried those but worth a try.

Good luck.