alt coin charts and main coin fluctuations

what happens when you are in an alt coin position. say you are holding xrp and trading it with eth. simulatneously eth / usd is going up, i am noticing that it is simultaneously going down on the xrp / eth chart (meaning the value of xrp..).. i don't know if that's such a good thing bc the chart is sort of getting distorted and it looks like people are selling... anyway.. this is just making my brain confused thinking about it.