Deks, I'm not sure how old you are, but it never gets any easier. My mother-in-law is 89. She's got health problems, but is still sharp of mind and able to drive and live on her own. She's outlived a ton of her loved ones, including her husband and daughter. It's VERY rough on her. But I don't think she'd rather have "kept her distance" from people.
When I was young, I said I'd never go to a funeral because they were awful and depressing. I was gloriously clueless and arrogant. When my father-in-law died 15 years ago, I had to go and I learned they are for the people who are left behind to gather and comfort each other. It helps.
I'm 53 now and I've been to too many funerals and also not had funerals/wakes that should have happened because of COVID. The idea of living as long as my MIL is a little scary because of the thought of losing people and animals I love. But I'd rather have the love and lose it than never have it (to badly paraphrase Shakespeare).
Meanwhile, with biological immortality, does the human race keep having children? Do we end up in "Mark of Gideon"? IMO, everything has pros and cons, and I don't think this is any different.
As I said, outliving people becomes a moot point when majority of people choose to live indefinitely as well.
If you are a 'people person', make an effort and seek out to connect with other people... younger ones even if you can/want to.
Plus, there are ways to pace yourself and be able to live with the premise you outlived those who passed away.
I'm 38 btw... but also had my fair share of experiences with death when it comes to other people (been to numerous funerals - even lost people I was very close to since I was a kid [family, friends, etc.] and I can tell you now that it didn't impact me almost at all because I already prepared myself for their possibility of dying well in advance - in fact the only being's death that hit me slightly more was that of our family dog... and even that didn't last very long - a couple of days really)... and as I said, I learned a long time ago to 'distance' myself emotionally from people just enough so that if they do die, I can live with it.
I also told myself I don't want to (and can't afford to) be bogged down by decisions of other people as its their lives and their decisions in the end... not mine.
I frequently think about death, other people dying, and even my friends and family because they all more or less 'resigned themselves' to the idea of dying... I decided to abolish the notion alltogether and told myself that 'death is NOT inevitable' (society seems to 'relish' this notion, and some people 'romanticise' it even - to me, that seems like a WASTE of life).
Maybe I'm different for choosing to distance myself from people, but it also works for me because I can't really connect with most other people in the first place (I am more of a loner - prefer even my own company, while others I can only really handle in specific quantities and smaller groups).
That, and I'm not religious to begin with (can't stomach that nonsense) - that kinda helps too because I immerse myself in science, 3D animation and other things.
As for whether humanity will continue to opt having children... well, it depends. Probably, but to a lesser extent.
An educated population has no need for 'population control' - so, no, we won't reproduce out of control (in fact, if you noticed, the countries with highest birth rates are also the poorest ones where basic necessities of life are not readily met or available to most - so due to the high mortality rates, people have more kids in an attempt to 'balance things out' - in more developed countries, birth rates are actually lower compared to the replacement line).
The longer the huamn life is and if you have access to basic necessities of life (including quality medical care), you will actually have LESS desire overall to have kids - also, if society were to STOP prompting people to keep having kids, that would also be helpful... religion promotes this ad nauseum... so does C(r)apitalism.
Personally, I never wanted kids and still don't (the notion was and continues to be apalling).
I don't particularly like kids (at least when it comes to the notion of having my own - shaping kids minds on the other hand might have some appeal which is why I'm considering a teaching position after my academia studies are done), and they are expensive (at least in the monetary system).
I ALWAYS recommend to people to first try adoption as opposed to having their own biological kids as there are too many children in dire need of decent homes (plus, I find it absurd that adoption raises too many barriers [financial and otherwise] for people who really want kids and are fit to be parents, yet those who have 0 inclination for parenthood and don't want kids to begin with have them in worrying amounts and then end up ruining their own and their kids lives).
P.S. I think we have gone WAY off topic here.

But it would also be nice for Trek and UFP to finally implement biological immortality in the mix and not villify it or present it as 'boring' or 'dangerous' or 'whatnot'.