There are not a lot of synonyms for the verb 'end up', but here are a few:
http://www.thesaurus.com/browse/end%20up?s=t
" The last time we met I became pregnant"
"end up" = finish
e.g. I started the race in front but I ended up last.
When I lost my job, I ended up in debt.
I went regularly to language classes, but ended up learning very little.
The correct sentence is:
"The last time we met I ended up pregnant".
It just means that last time they met, they had sex and she became pregnant as a result of the meeting.