bash: fork issue

I've got a problems with using terminal on macOS 10.12.3 and 10.13.3

When I try to run any command I get the following message: can't fork process: Resource temporarily unavailable.

I have already had such problem. Last time I was able to fix it - increase the number of process and my system looked like:

sysctl -a | grep maxproc
kern.maxproc: 2048
kern.maxprocperuid: 2048

ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
file size               (blocks, -f) unlimited
max locked memory       (kbytes, -l) unlimited
max memory size         (kbytes, -m) unlimited
open files                      (-n) 65536
pipe size            (512 bytes, -p) 1
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 2048
virtual memory          (kbytes, -v) unlimited

I thought that the problem was solved, but now I had that issue once again.

I was able to solve this problem this time with reboot - but it's strongly undesireable to reboot my mac every time.

Do you have any advise how to fix that problem once and for all?
Thanks in advance.