lcwl

Hi. I have been filling in self assessment for the last 2-3 years. I have multiple income sources including a full time job and a sole trader income. The sole trader is a loss but I don't think the loss is deducted from the total income from other sources. My questions are 1) Is the loss supposed to reduce the total taxable income? 2) If #1 is yes, how can I check if my previous tax was calculated correctly? 3) If #1 is yes, anything I need to do in this tax period to make sure the loss is deducted from total income?