I've been dealing with the sinus pain and pressure lately too. I think I might just have some seasonal allergies, though. I've never had them in the past, but allergies can come on any time. Or maybe it's just a head cold. The thing that sucks is that when I get sinus pressure I also get vertigo, and THAT makes me anxious, even if I know what it is. Feeling like you're falling all the time causes anxiety.
The muscle twitch thing could be brought on by a salt imbalance (too much or too little of magnesium, calcium, sodium, potassium). It could also be brought on by an activity, especially a repetitive one. This time of year I get tremors and weakness and twitches in my hands because of all the yard work; holding the edger, using the mower; it's repetitive use of muscles that I haven't used all winter, and they suddenly start getting all weird on me. The first couple of times this happened I was freaking out, but then I learned the patterns and figured out the cause. I'm sure there's something similar at work for you.