Hi Sammy,
Chronic tension can cause headaches that last and last. Also, having the viruses and sinus issues are surely adding to the issue.
Do all that you can to make sure that you are drinking plenty of water, you could be dehydrated from your illness. Also, you will want to keep any remaining mucus draining, and avoid a sinus infection. (which causes horrible headaches)
Next, I would remmend practicing Progressive Muscle Relaxation. Here is a link for intsructions for this exercise, and more stress relieving techniques. Practice these for at least 10 min, 3x a day. It should help.
http://www.stress-relief-exercises.com/
If you feel like you need further help, you could get a referral to a neurologist, and ask about treatment for your migraines.
I wish you the best. This has been a rough time for you. Please know that we care, and want to see you feeling better. Post anytime.
S.C.