Please help, doctors havn't given me clear answers!

[xther]

I have a problem! I've been mysteriously gaining weight at a steady rate. In the past 3 weeks I have gained 33pounds.  I kno, i thought such an amount in such a short time was impossible, i guess iwas mistaken. I'm 5"7 and used to be 108 so this is a excessive amount gained! It's so fustrating as my entire wardrobe no longer fits and the less i eat and the more i exercise i still gain the weight! It makes me depressive and some times irritable as the weight just keeps pilling on and i feel less inclined to socialise as i am ashamed of my ever expanding figure. Is it my metabolism, is it really slow???
On top of that i have been extremely fatigued, i sleep when i can for more than 8 hours and still feel weak, tired and run down. I have also random periods in which i am unable to sleep! I have changeable menst. periods changing from irregular or non existent. And when i do get them they last 2 days and are quite light. My body aches, i bruise easily and i am finding it hard to carry out day to day tasks as i find it increasingly hard to concentrate. For instance when reading everything becomes blurry words merge and i end up feeling tired and demotivated and with a mild headache to top it off. It became so difficult that calculating even simple mathematical problems takes a long time...arrgghhh! In addition to all that i have been eating 300 cal or under a day and doing about 30-60minutes of exercise a day if feeling up to it. So i dont understand why i gain the weight!
Recently i suffered from a moderately severe loaded colon which made me suffer from nausea experiencing frequent vomitting. This was resolved however i am still suffering from constipation, is this normal?
I recently had a blood test done and the doctor didnt give me the results for thyroid only stating it was boarderline low and perfectly fine nothing to worry about. Yet im beginning to suspect its hypothyroid as it runs in my family. My blood pressure is low 52/90, B12 was 268 pmol/L, Ferritin 10ug/L, Iron 13umol/L, TIBC 81 umol/L and transferrin sat 16. Im not sure what to make of the results can someone help me please?
If its not hypo or metabolism can someone help me understand whats wrong?? If so do you have any tips for loosing the weight, (besides diet and exercise as they are obviously failing me)?

[DLA]

By stressing your body out with the tiny amount of calories and all the exercising you are further supressing your immune system.  Any thyroid problems cause your immune system to weaken, even if they aren't an autoimmune disease, so you need to do all you can to help your immune sytem, not make it even worse.

Dac

[zaksmom]

While your symptoms might be pointing towards hypothyroid, you are only making matters worse by eating 300 or less calories a day!  That in itself will make you weak and lethargic, cause digestion problems (constipation), and low motivation or concentration!  Your body is designed to use the calories you take in and use them in the energy you burn!  I know you're paraniod about the weight gaining issue, but starving yourself is only going to make that worse.  If your body goes into starvation mode, it will keep every calorie you put in it -- you will not burn any with your exercising!  

I know it is frustrating, I have similar symptoms (yes, weight gain) - but since my blood tests seem to point toward the "normal range" there is nothing the dr. will do.  He just says to be patient and wait until the numbers change.  GRRRRRR!  I hope you're able to get this taken care of and feel better soon!