I did have my period every month, but not feeling very well these last couple of weeks, on 24 December I did do a pregnancy test, which came up with 2 lines but 1 line slightly fine, on the 1st January I had my period for 5 days and just last week the 25 January I had my period again for 4 days, and it was heavy flow. Feeling nausea everyday, the whole day, dizziness and also my pants do not fit anymore but it could not be that I gained some weight because I was also not eating very well. Could I be pregnant?

At this point you need to see the doctor, we were not there to read the pregnancy test, seldom are there false positives, so positive means you are, or where pregnant, unless you misread it.
Possible issue of miscarriage of course.

So you need to have it checked with your local doctor to confirm if there is a issue and if there is what is it