Water retention?

29M. I’ve been obese for much of my life. In the past couple years, I’ve dropped from 370 to 260 lbs. I’m 6’3.

I’m in week 5 of my first cycle, 500 Test C per week, split into 2 doses E3D. I’ve lifted weights for years, and power lifted years ago when I was much bigger/fatter. I’ve been lifting consistently weekly for the past few years. I’m active, lift 6 days/week and have been eating in a calorie deficit of 3-400 per day. There have been a few days I’ve been net 0 on calories, but in a deficit 90% of days.

In the 5 weeks of the cycle, I’ve gained 20 lbs. I am much more toned, actually look and feel less fat, and my clothes still fit the same. I started getting some mild high e2 sides (sensitive nipples) and just started 12.5 Aromasin last night.

Anyway, can I assume this weight is water weight from high e2? I’m going to get bloods done, but wanted to wait until 6-8 weeks in. Anything else I should do or look out for?