What Causes Drastic Weight Gain Along With Hair Loss And Dizziness?

In 2000 I was in a traumatic car accident. My colon was ruptured and approx. 60cm of large intestines were removed. I had a colostomy bag for one month and then it was reversed. I do not know if this has a lot to do with what s going on now or not, but that s my background. Fast forward to now...I m thinking I have an iron deficiency or something of that nature. Within the past 5 years, looking back now I can see that I have gained 20+ pounds and cannot get it off, my hair has thinned and I am very pale compared to what my natural color used to be. I m always tired, even after a good nights rest it s hard for me to get up in the morning. It s a task to concentrate at work because I feel like my brain doesnt work very quickly all the time. And here lately, past few months, I ve started getting random spurts of dizziness to the point where I feel weak as if I could pass out. Can anyone point me in the right direction?