Please don't feel guilty. Both my husband and I (separately) went to see our DGC in their back garden. We sat at the bottom by their back gate and they were playing on their trampoline at least 20 feet away. It's the only time we've seen them in person, and bearing in mind that before lockdown we had the younger one twice a week when he wasn't at nursery and collected the older one twice a week and had her after school, it's been a bit of a shock to the system!
You are being sensible, not taking unnecessary risks and coping in the best way you can. Not something to feel guilty about at all.
BTW, as I type our next door neighbour, who is due to give birth next week, and her husband are entertaining two friends and their child in their garden. Pizza and beer being served, pizza all taken from the same plate, their child and their friends' child playing on the trampoline. Now THEY are being totally irresponsible, IMO! Can't believe they think they are following any rules or restrictions - but then they are the sort who don't believe any rules apply to them............