Late period after Hsg or...?

I had an HSG on day 8 of my cycle (everything is in working order), and now I am about 4 days late for AF (usually very regular). Nothing but negative tests so far. Anyone else have an HSG cause a late period? Is this normal? I know that you can have a better chance of conceiving right after the test (medical assistant went over this with me during), but I also don't want to get my hopes up.