First of all don’t panic Second of all you cannot switch sections so yeah even if you score -ve marks it doesn’t matter as it’s just a mock. People suggest giving one mock before starting prep only to understand the pattern of the test and to see where you stand

If you want you can skip this mock and start the prep but I would suggest just give your 2 hrs and attempt it without any pressure. After that start the preparation with whatever classes or course you have enrolled in and prepare strategically rather than doing random stuff and be consistent