Hey, loner12345 - change this name, you're certainly not alone.
I have very good friends and family that I pestered for years because of how I felt, I worried too of my effect on them but over time I realised that you are the one needing the support just now, so think of only yourself at this moment.
You are young and have been through a lot already, your kind and sensitive. I can 100% say you are not crazy, it's a thought and thoughts come and go and when they do your feelings come and go! This is why thinking is powerful, it must stay positive, relaxed and relative to your surroundings. All your thoughts should be rational, when they are you have a balance on life, when you begin to worry your mind is telling your body to be ready to either fight off the problems or run away. This leaves you feeling tired and sad but believe me it's normal. Every night think positive before you go to bed, breathe deeply and slowly, count up to ten and back to one or just imagine your toes, head, arms, legs, body all relaxing. Actually tell yourself and your body parts to relax one by one.
Please speak to a close family member, continue with seeing your doctor and don't be worried to take some medication to help you balance your bodies response system. Ensure you have a breakfast, lunch and dinner even if you don't feel hungry. One great thing to relax that I found was to drink Camolmile tea, I'd put honey in as the sweetness and nutrition is good for you.
Look after yourself and slow things down, take time for yourself.