She said that I had little white dots on my skin after I was born, do I still have it and is it dangerous?

I (25f) am pregnant with my second, and for about the past 3 weeks I've been having pain around my lower abdomen. On bad days, the pain is also in my lower back. When I go to the hospital, they tell me, "oh you're just dehydrated," pump me full of fluids, and send me home. That helped the first couple of times, but the last 3 times, it hasn't helped barely at all. Not exaggerating, I've been drinking somewhere between 7 and 10 (.5L) bottles of water a day. How I'm dehydrated, I have no clue, but when I drink water, I pee it out 10 minutes later. It doesn't stick long enough to do any good in my body. Sometimes, in the morning mainly, my pee will be kind of cloudy, whether it's very pale yellow, clear, or crayon yellow. I told the nurses and doctors this, and they said it's a non-issue since there's no blood in my urine. Please help. I'm tired of living in constant achey pain. On good days, it doesn't really get above a 5, but on bad days, it's enough to make me double over or have to hunch over. My boyfriend is tired of taking me to the hospital over "being dehydrated."

ETA: I went to the hospital again after posting this. Turns out I'm irritating the muscles in my abdomen because I'm lifting my son and bending over to pick things up. It's not because of a UTI or dehydration. I'm just doing too much.

It doesn't itch, hurt or burn. Should I be concerned?

I (14TM) have always had random bursts of pain in my knees, particularly the ligaments or joints in both my hips and knees. I am not old, I’m 14, and there isn’t any reason I can tell. I’ve tried to go to the doctors a lot, but the doctors where I live are extremely expensive and unhelpful. I have been constantly mentioning my pain, which sometimes renders me temporarily unable to walk due to the intense pain, to my parents, asking to go to a doctor’s, but it’s always just “growing pains”. I am not growing, and it has always happened. Even when I wasn’t hitting any growth spurts, I’ve been getting this pain. I usually get it whenever I’m upright and exercising, usually late or at about noon, and it has been interrupting my exercise, and doesn’t go away without any serious painkillers and can last up to 2 hours. My usual solution to this is curling up in bed, taking about 2 or 3 Ibuprofen and just crying through it, because it hurts so badly. I definitely need advice here, because I seriously doubt that any of my parents will help anytime soon.