Go to the chiropractor...I had the same issue and it was a pinched nerve..
Sciatica gets worse...you can find temporary relief but it will most likely go away once you deliver. I use natural oils. I have degenerative disk disease, arthritis and have already had one back surgery out of 3 other recommended. Peppermint, thieves oil and geranium are great. I rubbed peppermint oil on my knee yesterday before a severe cold front and I still don't feel it! There is another one you can mix with these that mimics a natural morphine that is completely safe...it's a weird name like cojoba or something. Google it!