Your condition sounds pretty serious, so I would hate to give you the wrong advice, but I will let you know what worked for me.
I was also at a point in my life a year ago when I just didn't understand why my health was going downhill, especially after quiting drugs, alcohol, and eating a good diet for a few years. I had a horrible sinus infection for 3 months and had the most painful hemorrhoids. I didn't understand what was causing my body to react this way.
I came across the drnatura.com website and learned about colon cleansing and parasite cleansing. I then found curezone and continued to learn more about how to detox, strengthen, and heal my body.
I think that colon/parasite cleansing might be a good start for you. The herbs to help get rid of parasites will strengthen your immune system and help stop sore throat and yeast infections, and may also help your stomach pains if parasite related. I haven't had one headache, stomachache, sniffle, etc. since I did this. The Colon Cleanse is always a good idea when trying to restore your health because once it is clean your body will be able to absorb nutrients needed to heal other areas. In your case, with rectal bleeding, you might have to take some caution.
Depending on how toxic you are, cleansing reactions may be anywhere from unnoticable, to even worse than before. This often discourages people from following through with a cleanse, and then they go back to their regular lifestyle. This is a big mistake when trying to achieve better health and can lead to even more serious problems.
Sorry if this was too long. I just hope this will help you find your path to optimum health.