Unexplainable Weight Gain (GRRRR)

Sebani

Hi All. I'm sure you see this all the time but I really can't fathom why I am gaining weight. It's super frustrating AND discouraging! Let me give a background on my history:

I usually I'm 5"5/5"6 and average 133.5-135lbs in the morning but as of lately I've been weighing in at 135.5+ the past 4 days. I work out 5 times a week and do solely weight lifting (no cardio).

I wouldn't say I have been eating the healthiest lately but certainly not poorly enough to be seeing the current weight on my scale (138lbs) as of 9:51 pm today! I usually lose 1-1.5lbs overnight so I can, with certain confidence say that I will weight 136.5+ tomorrow morning when I weigh in, which is a DISASTER. I literally haven't weighed this much in the morning in over 6 months and I can't go back to that weight. I'm literally in a state of panic. I know most of you will think that it's muscle weight but I literally have been working out the same routines all summer and didn't gain (or lose) a single pound. So WHY NOW is my question.

Also time of the month is in 5 days. I know it's normal to gain some weight during this time but I've never gained THIS much so I'd like to know your thoughts? Please and thank you!

Today I had:
Breakfast: 1 plum and a cup of coffee (1tbsp of Coffee Mate liquid form)
Snack: Cup of Coffee with 1 tbsp of Coffee Mate (liquid)
Lunch: Spaghetti and Meatballs (reasonable portion), an apple and 1 piece of a spicy salmon maki roll
Snack: 1 Venti Skinny London Fog from Starbucks
Dinner: 150g piece of salmon, 60 g of basmati rice and broccoli with cheese

This doesn't seem like an awful diet, yet here I am