If you are faced with having positive earnings (€) and negative returns (%), or the opposite, do not worry. Even if it sounds wrong, it is quite correct! Returns are calculated separately from contributions and withdrawals. If your return is positive, it is because your portfolio has increased in value since your first investment. Conversely, if your return is negative, it is because the value of your portfolio has decreased since your first investment.
If your monetary gains are negative, it is because you deposited the majority of your investment just before the value of your portfolio fell. Conversely, if your earnings are positive, it is because you deposited the majority of your investment just before the value of your portfolio increased.
I make an initial payment of €1,000 on the first day. Imagine that the market performance is 20%. My portfolio will gain value to reach €1,200. If I invest € 10,000 more just before the market performance falls by 10%, I will lose more (€1,120) than I had gained (€200). Thus, my gain will be negative (-€920) even if the performance of the market (the return of my portfolio) remains globally positive: +20% + -10% = +10%.