So I got into BTC in november and bought in around 15k. I was a complete newb and saw alts booming so eventually decided to invest everything in alts, at which point I had about 0.58 btc's worth of alts.
Obviously then the crash happened, and I decided to hold everything until now (bad decision) and now I'm at a huge loss with all my alts - went down to around 0.13btc eq the other night.
I've missed out on a lot of profit over the last 3 months and lost a lot too by just holding. I want to get some BTC/ETH back in my portfolio and maybe try to make a few weekly trades, the problem is I'm at such a huge loss with all of my alts I don't want to sell them for such a loss at this point.
I'm not sure if I should just take a loss or hold until they go back up (down at least 60% on everything). I don't know anything but I have a feeling BTC will go back to around 50-55% market cap
You have to make your decisions based on your expectations. Given you said you expect bitcoin share to increase you should be moving your funds to bitcoin.
My own opinion is that alt-coins are nearing their bottom price and will recover soon, the only scenario I see in which they don't is if the whole market continues to slide.