Does it have any grammar problems?

I've been taking levothyroxine, starting at 25mg as the dorctor suggested. I thought taking a few pills would put an end to my problems, how wrong I was. After having that shit blood test, my TSH level kept going up instead of coming down, still the dorctor suggested upping the dosage to 50mg. I kept wondering why, she said the TSH is rising as I didn't have sufficient thyroid hormones in my system. Levothyroxine has to convert to T3 which is the active hormone required in our cells (T4 is the inactive hormone). I don't want to take any more levothyroxine, because before I went to the doctor, my TSH level was a little higher than normal, but now it's much higher than the original.

Has it grammar problems?

I've been taking levothyroxine, starting at 25mg as the doctor suggested. I thought that taking a few pills would put an end to my problems but how wrong I was! After having that holy shit blood test, my TSH level began going up instead of coming down. Still the dorctor suggested upping the dosage to 50mg. I keep* wondering why she said that the TSH was rising as I had insufficient thyroid hormones in my system? Levothyroxine has to convert to T3 which is the active hormone required in our cells (T4 is inactive). I don't want to take any more levothyroxine, because before I went to the doctor my TSH level was a little higher than normal but now it's much higher than it was at the start**.

*I am not quite sure where you wanted to end your sentence here (where to put your full stop), so am unclear about your meaning?

**If this was your meaning?

Very well written, but please take more care to end and start your sentences. One sentence should be one new idea. Also take better care of your commas.