Glad you're taking the natural route to dealing with your health problems. Start keeping a journal of what you eat and do and how you feel. Over time, this will help you identify things that make you feel better -- or worse.
I'd start the cleansing process with an elimination diet. Irritable bowel and sinus problems are often a result of food (or other) allergies. If you stop putting the irritant into your body, your body will slowly recover. Cleansing will speed the recovery process.
Elimination Diets are restrictive, but you don't have to go hungry. You eat as much as you want of a very few foods for a couple weeks, then gradually re-introduce one food at a time, noticing which ones cause problems. Notice what you crave -- that often points at an allergy. I had a friend who nibbled on uncooked pasta -- she was allergic to wheat.
The Elimination Diet should be limited to a few foods that aren't allergenic. Avoid all the usual grains, wheat, corn, rye, oatmeal, rice,etc. Use quinoa, millet, amaranth, whatever is different from your usual diet. Stay on the limited range of food diet for at least two weeks. Doing saunas, detox baths, skin brushing, rebounding, etc. helps your body return to balance. Flushing your sinuses with salt water a couple times per day (using a netti-pot) is also good.
When your bowel function has returned to normal and your sinuses start to clear, you might try a liver flush, making sure you've been eating lots of apples the week before.
Add back one food per day, watching what causes you digestive trouble or congestion.
Perhaps someone else can recommend good herbal teas for your conditions. I use ginger, but it might be overly stimulating for the digestive tract. Peppermint might be good.
An Elimination Diet limited to apples, veggies, almonds, uncommon grain and poultry would be something like:
Morning drink: 2 Tbs fresh lemon juice in a glass of pure water.
Breakfast: Apples chopped over left-over cooked grain from dinner, sprinkled with cinnamon and sliced almonds. Eat as much as you like.
Mid day snack: Veggie sticks (or apple slices) with fresh almond butter, as much as you like. Herbal tea.
Lunch: Big green salad, with a squeeze of lemon and grilled fish or chicken on top. Herbal tea.
Mid day snack: Veggie juice, diluted with pure water to taste. Handful of almonds.
Dinner: Vegetable soup, made with chicken broth, cooked whole grain millet or other uncommon grain, eg. amaranth, quiona, etc. Grilled chicken, turkey, etc. Cooked green veggies, dressed with olive oil and lemon juice. Fresh green salad. Herbal tea.
Desert: At least a couple hours after dinner, apples, drizzled with honey, sprinkled with cinnamon, baked if you like. Herbal tea.