Hello, I am 28 and am trying to go sub 1:30 in a half marathon end of March. I have been running about 10 miles a week for the last year and a half and then spiked it up to 22 miles a week average (for 4 weeks) and a peak week of 28 miles before my first half marathon last week. I ended up finishing it in 1:43, but was on pace for 1:40 until mile 11, when I started getting cramps. My training consisted of mostly easy running, some tempo run and the longest run was 11 miles.
What training plan do you suggest me to get? Should I get a coach instead(how much are those)? I am happy to train 4 times a week till february and spike it up to 5 times a week for 3-4 weeks.