Flushing and feet/hands turning blue can happen with Raynaud's. There may be an underlying condition. Here is an informative site:

http://www.cedars-sinai.edu/Patients...henomenon.aspx

I'll repeat a suggestion, that I make now and then... and that is keeping a journal to see if you can isolate a trigger.

Cold feet and hands can come from too much caffeine intake. After the hands/feet start to warm up they tingle and may flush and change color. Excessive smoking (nicotine) will do this too.

Some foods like the nightshades which includes all the pepper family can affect the nerves as well.

Check your shoes to make sure your toe box is roomy and also don't tie your shoes too tightly --this compresses the instep and the nerves and blood vessels can be damaged.
This website has lacing alternatives on it that can really help.
http://www.northcoastfootcare.com/

I bought the spiral laces (made for kids) ultimately and use those on my athletic shoes...made the world of difference for my feet and eliminated numbness spells.

You might investigate an infectious disease specialist for some viral testing and Lyme testing. I had blood titres (levels) run when I had shingles and that was very useful for me. If I were you I'd do the lysine treatment now... you might be surprised at how useful that can be. At least 2 grams a day. That feeling "sick all over" suggests a viral thing going on. I use Lysine in spurts when my shingles arm acts up or I get "flu-like" symptoms. It seems to work within 24 hrs for me.