Employment and Self Assessment

FiFiupnorth

Hello all. I’m new to the site, (although have often referred to it). I’m self employed, (sole trader) since November 2017 and do my own tax returns. My expenses are high, (mostly software and mileage) and only work part time so am below the threshold for income tax. I also work 9 hours per week in paid employment which I started in March 2019. Prior to Nov 2017 I was in the same
line of work, but worked on an as and when basis as a paid employee up until Oct 2017. I was on the phone to HMRC today about something unrelated, (Scottish rate of tax contributions for national insurance different) and the man I was transferred to was incredible grumpy and interrogating from the start. I had a query about the tax I was charged in my first month as an employee in 2019, (my employer used emergency tax) and he demanded I login to HMRC and look up my tax return for 18/19 which he told me was wrong as I’d left out information about earnings from my employer. I told him I only started working in March 2019 so had one month of earnings and everything else is self employed income. He told me I’d left put earnings from my other employer, (who are now clients as I’m self employed). However I haven’t received earnings as an employee from them since 2017. Now I  am
worrying that this should have been on my tax return, but surely not for 18/19 tax return? Can anyone put my mind at rest? Earnings are usually there on the HMRC page when you go to do the self assessment. He is sending out a proof of employment form. Wishing I hadn’t phoned them.