Synthroid & Thiazide Drug Interaction

Hello,

I have been taking Norvasc 10mg and Hydrochlorothized 25mg (1/2 pill per day) for several years for my High Blood Pressure.  Recently, I was diagnosed with Hashsimoto's and started taking Synthroid 50mcgs in hopes thta it would alleviate many of my HypoThyroid symptoms (TSH = 4.120).  

I've read that Thiazide drugs may somehow interfere with Synthroid, but I haven't been able to find out anything specific.

I have been doing OK on Synthroid the first two weeks, but going into my 3rd week I noticed that I have developed a headache for the past 2 or 3 days.

Right now I take all three medications in the A.M. together.  Should I take my Synthroid seperately from my Blood Pressure Meds?

Thanks

~Dee