Sever do Vouga is indeed quite remote, different from areas like Lisbon or the Algarve with high percentages of foreigners including americans where you probably would feel less lonely.
My father is portuguese and my mom who is dutch also came to live here for love but I think she still regrets the decision sometimes when things are not going to well...
I am from Sintra, near Lisbon. There is an American School here close where children learn English (US) and Portuguese and where they wouldn t feel the transition so baddly. I think a high percentage of the school students are american. I cannot advise you on what to do, but if there is anything I can do please let me know. If you go to the Monster Jobs website and select European adds, you will find that there are a lot of foreign companies advertising for positions in Portugal for non-portuguese speaking people. I don t know what kind of work experience you have but you can always take a look.
Best of luck!
Ines